Here I am studying MSc in Engineering but watching this rather simple video I guess I needed something as simple and clear as this video after being lost in the details, something like this reminds you of the essence of these basic concepts. It's not a shame to go over these simple terms (other simple terms also) every once and a while as I get some sort of refreshness and a slight smile of how things were nice and simple. Great video, thank you.
I dont know if anyone has noticed but Professor Dave seems to know a lot about the science stuff. All jokes aside our videos are really helpful and I watch them every time we learn a new unit in physics.
I use to hate ur intro and the way you explain things. Lately I've been realizing that you are proficient when it comes to concepts especially when it comes to physics. Keep this subscription forever and I hope you continue uploading videos. Thank you for helping an electronics engineering student who is so terrible at physics.
Proffersor dave, thank you, I had a difficult time answering this question "in a frictionless enviroment, would an object of heavier mass have greater ke than a lighter mass?" until I watched this vid. Wish you the best in your future endeavours.
As far as I'm concerned it's a lot easier to understand the truth of 9/11 when you realize Einstein's gravity, which Neil deGrasse Tyson says superseded Newton's gravity, does not accelerate objects down to the ground, and does not push objects down with a force. And when you do, you'll also realize objects need a support from below, where the one and only force that comes from below to give objects their weight, then you'll realize that nothing comes down unless that support underneath the object is first removed or weakened. And if that support below is weakened to the point where the object will become lighter, the object will then descend with the illusion of apparent acceleration. There are many, at least a dozen RUclips videos on Einstein. They all talk about Inertial Frames of reference, which both Newton and Einstein agree on, which it is when an object is not accelerating. They're both totally opposite as to when you would say an object, influenced by just gravity alone, is being accelerated. But we know it is a force of acceleration in ONE direction that is the explanation of why mass has weight in the OPPOSITE direction, like how you fall backwards when the bus takes off forwards...then you've figured it out who makes more sense about inertial frames of reference...Einstein was right, free fall is not acceleration, free fall is not kinetic energy, because free fall is weightless and is standing still. ruclips.net/video/E43-CfukEgs/видео.html
I did it by other method First I found k.E 1/2×50×11.2×11.2=3136J As it transfers 1539J to another body so 3136-1539=1597J So new kE is 1597J 1/2mv^2=1597 1/2×50×v^2=1597 ( as mass is given 50) 25v^2=1597 V^2=1597/25 V^2=63.88 V=7.99
I did it the same way as you @cartoon stories. I don't completely understand Dave's way of working this out. Would be good if he could add an explanation to his calculations.
I remember when I was a kid jumping on my trampoline I’d take my mums keys and let them go as I was coming up or falling back down but what supprised me (besides the fact that the keys and I fell at the same speed) was that when I let them go as I was coming up they would go higher then me but then still fall at the same speed, back then I didn’t know what gravity was or that things fell at the same speed but it was so mesmerising letting go of the keys because they’d kind of just move in slow motion as they were faking
He sticks to rigor and he's fun yet which is rather a rare combination. Only someone gifted can do something similar. Saludos desde la República Domincana!
2 questions: 1) Between step 2 and 3 of the answer for the comprehension, how did -1,539 *J* become -1,539*kg m^2/s^*? 2) Between step 3 and 4 of the answer to the comprehension, how did (11.2 m/s)^2 turn to 125.4 m^2/s^2? Btw great video 👌😄
I wish I knew about you when I had to take Intro to Physics like 2 years ago. I would've gotten an A NOT a B! :( Oh, well ....understanding it is more important than a grade.
Thank you for explaining this! I was wondering why it was necessary to ascribe an object at rest "potential energy" when it hasn't moved and isn't necessarily going to. I was wondering why we can't just say it has energy when it's actually in motion. But the pulled arrow on a bow and compressed spring examples illustrated the point, and then the clarification that potential energy exists due to an object's position in a *field*, and often when we say potential energy we are talking about gravitational potential energy. I hope I understood that but that was my take away! Thanks!
Your video was short and helpful compare to other videos. I kinda got the material gradually. When I do the problem, I almost got it except the negative signs. I wonder why is negative ?
5 years late but its negative because the question states "1539J of energy is transferred" implying that its work done BY the system which is always negative like professor dave said earlier in the video
I wasn't careful enough so didn't take into consideration that W has to be negative. Just by the change of a sign I got my results = 13.674m/s. So just by the change of a sign I gained more energy after the impact x'D
I am doing masters in theoretical physics . i was studying about electrons EPE in a experiment but suddenly forgot about PE . i guess more knowledge you gain it gets all sort of messed up in head , it needs to be cleared out time to time 😂.
Keeping it simple, I discovered that all animate objects are Kinetic Energy & all inanimate objects are Potential Energy & only Kinetic Energy can become Potential Energy & not the other way around. ~Guadalupe Guerra
I'm thinking that the reason for W being negative is for a similar reason that exothermic reactions in chemistry are negative. They transfer or "release" energy into their surroundings, which is represented by a - sign. Idk if this is a proper way of thinking about it, or if it's even correct, but it worked for me so I'm kk with it.
thank you so much sir !! your videos are short and clear. initially I hated physics but after seeing your videos I got clarity about concepts . Your doing great job.
Plz sir I so grateful for ur lesson and love it, it's more understandable. But plz sir can u illustrate ur calculation, I am finding it difficult to... Plz 🙏🙏🙏
@prof Dave, Just want to ask questions for clarification. According to the Kinetic Molecular Theory "particles of matter constantly move". Kinetic Energy by definition is often defined as the energy of an object due to its motion. At a macroscopic level, we identify and differentiate Kinetic energy and Potential energy based on the observable motion of an object. Simply, if it's moving there is KE (energy in motion). Otherwise, PE.(energy at rest). However, at the microscopic level, as per the KMT, particles that make up matter move constantly, and this is where my understanding of KE and PE becomes a bit fuzzy: 1. Considering KMT - particles of matter are always in motion, does Potential Energy form really exist? Hope you could give clarification on this.
This is the equation I came up with to solve for vf in the comprehension section at the end of the video. (2((w)+1/2(m)(vi^2))/(m))^(1/2)=vf What's wrong with my algebra? I'm extremely frustrated.
What are the difference between kinetic energy and potential energy? I discovered that all animate objects possess kinetic energy, while all inanimate object exhibit potential energy. Kinetic energy can be transformed into a potential energy, but the reverse is not true. Additionally, potential energy remains constant, regardless of whether it is in motion or at rest. ~Guadalupe Guerra
I have an interest in kinetic energy and I am looking for a definition as we as an example. I also think it should be broken down and simplify. I know that a ball sitting on the ground still has kinetic energy.
A ball sitting on the ground has zero macroscopic kinetic energy in the reference frame of the ground. If you look at it from a different reference frame, like the center of Earth, it will have kinetic energy as a consequence of moving with its immediate environment. It also has internal kinetic energy at the molecular level, as this is how objects store their thermal energy. Every object that isn't at absolute zero has internal kinetic energy.
Wouldn't a ball in my hand have a kinetic energy force pointing towards my hand because it's exerting a force on my hand? Or is that called Potential Energy just because it's at rest?
professor dave i should tell u this but u should had explain that kinectic energy as u did with potential energy . You explained the potential well but i ma bit confused in kinetic.
I don't understand how the gravitational potential energy can depend on height in this simple way. Suppose you take an object and increase its height by 100,000,000 kilometers; does such an object have more potential energy or less than an object at 10 meters above the ground? The object at 10m will experience much greater acceleration because the object at 100,000,000 km is so far away and thus experiences a much weaker gravitational field. Does the definition assume a uniform gravitational field throughout space?
Would be nice if you kept your terms constant, initially you're using 1/2mvf^2 and later on in the comprehension check it is marked as 0.5mvf^2... Very confusing when you're learning! :D
I have a question. In the part of the work-kinetic energy theorem, you said that when the work is negative, the system is doing a work, but in my opinion, the force is doing a work that makes that the kinetic energy of the particle decreases, and this work can be computed as the subtraction between final kinetic energy and initial kinetic energy of the system. What do you think?
When net work is negative, this means work is leaving the kinetic energy of the object we are studying, and the object decreases its speed. This could mean energy is being stored in the form of potential energy, or it could mean a non-conservative force such as kinetic friction is converting the energy into heat and taking energy out of the mechanical domain. Potential energy is a shortcut to calculate the work done by conservative forces, because it is a state function instead of a path function. It only depends on initial and final states, rather than the details of the path. When we exclude forces associated with a potential energy, and only study the non-conservative forces, the work-energy theorem changes from "KEfinal = W + KEinitial" to "KEfinal + PEfinal = KEinitial + PEinitial + Wnc". The sum total of PE+KE is what we call the mechanical energy; i.e. the energy we can exchange reversibly through the mechanical actions of the system. Wnc is the work of non-conservative forces. Such as work done by human forces to initiate the energy of the system, or work dissipated as heat by frictional forces, or work done on a human as human forces guide the system to rest. Any force that can add or subtract energy to an object in motion, for which we don't track a potential energy.
@@michdawnespera9578 Yes. If kinetic energy is decreasing, that means the net work being done on the object is negative. Is there a specific issue I could help clarify, that I'm not seeing in your question?
I understand this except for the math at the end. I get why those values plug into the equation the way they do, and I know that joules is kg m^2 / s^2 in SI base units. After that I'm stuck - I can't see how the equation has been simplified and rearranged. Help please Prof. Dave! Loving your videos btw
so first we just multiply 50 kg by 0.5 in both terms on the right side to get 25 kg, and then we factor 25 kg out of the binomial to get 25 kg times that reduced binomial then when we divide both sides by 25 kg we lose kg on the left, ending up with m^2/s^2, we add the other m^2/s^2 term from the right side, and when we take the square root its m/s! if this is still tricky, i suggest watching lots of my math tutorials!
+Professor Dave Explains Thanks Professor Dave. It's a long time since I studied maths at school so I'm a bit rusty, so yeah I will have to watch some of your maths videos. (Yes "maths" with an s - that's how we say it here in the UK :) )
Here I am studying MSc in Engineering but watching this rather simple video I guess I needed something as simple and clear as this video after being lost in the details, something like this reminds you of the essence of these basic concepts.
It's not a shame to go over these simple terms (other simple terms also) every once and a while as I get some sort of refreshness and a slight smile of how things were nice and simple.
Great video, thank you.
I dont know if anyone has noticed but Professor Dave seems to know a lot about the science stuff. All jokes aside our videos are really helpful and I watch them every time we learn a new unit in physics.
Professor Dave. You are frik'n smart man. Thank you for sharing this video on RUclips. You're the best!
I use to hate ur intro and the way you explain things. Lately I've been realizing that you are proficient when it comes to concepts especially when it comes to physics. Keep this subscription forever and I hope you continue uploading videos. Thank you for helping an electronics engineering student who is so terrible at physics.
@Ashay Playz he said sorry. And what do u expect the world is full of hate
bro is the physics jesus
💀
What????
¿¿¿¿tahW
🧗💨✔️
Nah, he’s the Science jesus
Proffersor dave, thank you, I had a difficult time answering this question "in a frictionless enviroment, would an object of heavier mass have greater ke than a lighter mass?" until I watched this vid. Wish you the best in your future endeavours.
As far as I'm concerned it's a lot easier to understand the truth of 9/11 when you realize Einstein's gravity, which Neil deGrasse Tyson says superseded Newton's gravity, does not accelerate objects down to the ground, and does not push objects down with a force. And when you do, you'll also realize objects need a support from below, where the one and only force that comes from below to give objects their weight, then you'll realize that nothing comes down unless that support underneath the object is first removed or weakened. And if that support below is weakened to the point where the object will become lighter, the object will then descend with the illusion of apparent acceleration.
There are many, at least a dozen RUclips videos on Einstein. They all talk about Inertial Frames of reference, which both Newton and Einstein agree on, which it is when an object is not accelerating. They're both totally opposite as to when you would say an object, influenced by just gravity alone, is being accelerated. But we know it is a force of acceleration in ONE direction that is the explanation of why mass has weight in the OPPOSITE direction, like how you fall backwards when the bus takes off forwards...then you've figured it out who makes more sense about inertial frames of reference...Einstein was right, free fall is not acceleration, free fall is not kinetic energy, because free fall is weightless and is standing still.
ruclips.net/video/E43-CfukEgs/видео.html
I did it by other method
First I found k.E
1/2×50×11.2×11.2=3136J
As it transfers 1539J to another body so 3136-1539=1597J
So new kE is 1597J
1/2mv^2=1597
1/2×50×v^2=1597 ( as mass is given 50)
25v^2=1597
V^2=1597/25
V^2=63.88
V=7.99
I did it the same way as you @cartoon stories. I don't completely understand Dave's way of working this out. Would be good if he could add an explanation to his calculations.
robert stewart yes you're he should add more explanation/information about equations or calculation specially in physics
I'll... just watch the video, thanks. but great explanation. :)
yep i also did it this way
Can I ask how we got the 7.99 at the end
W= mad
w: why you have to be mad at me?
Noble prize is for you
Wario's and Waluigi's origin story...
See W= F.d
So now, F=ma
That's why m.a.d
😠
2022 and still helpfull !!! The content he teaches in under 5 mins is just awesome ! Loved it ❤
2023 and still helpful
@@nafyssacisse 2024 and still helpful
True
im watching this in 2020 and this rlly helped me. I love ur intro!
I looked at your post date and it said "7 months ago" I was like are you sure it's 2020?!?!
WTF it's been a loooong year :'(
Me too
Hey from the future haha can’t believe you wrote this a year ago
hey from the further future, I don't know why I am doing this.
Hey from further further future, i am doing this to ignore the work in front of me
THANK YOU SO MUCH! I HAVE TO WRITE AN ESSAY ABOUT POTENTIAL AND KINETIC ENERGY AND THIS HAS HELPED ME A LOT :)
Just discovered this channel but wow, really good, his explanations are simple and easy to understand
Wow !
You defined potential energy quite perfect .
Concepts are very clearly and briefly explained. I like Prof. Dave's videos.
I feel so proud of myself actually getting the practice problem right lol. Thank you so much!
I remember when I was a kid jumping on my trampoline I’d take my mums keys and let them go as I was coming up or falling back down but what supprised me (besides the fact that the keys and I fell at the same speed) was that when I let them go as I was coming up they would go higher then me but then still fall at the same speed, back then I didn’t know what gravity was or that things fell at the same speed but it was so mesmerising letting go of the keys because they’d kind of just move in slow motion as they were faking
Have an exam tomorrow at 10:30 AM. Your videos are really helping me study last minute.
Thanks Professer my school teacher showed us the video and it helps me alot.
just understood, thank you Professor! I have realised it is called potential because it is potential.
Since the start of online classes, some teachers are not at all efficient in explaining this. ARIGATO GOZAIMASU DAVE SENSEI!!!!!!😄
Remember this
the intro was like a primary school teacher and then he starts bamboozling my brain
Dave just taught me Hour 1-2 of Physics 4a in just 5 minutes, that's insane!
Our school played this for Science! :)
Samee
you're luckyyyyy
not very good
This man taught me in 4 mins what my science teacher couldn’t teach me in 4 months
This was a great helpful video when discussing with my middle school student! Thank you
Ur kid's in the wrong school if he learning potential energy in middle school
In which standard you are ?🤔
I enjoy Professor Dave's videos, helps me learn subject better!!
Thanks this is really helping me I have an exam tomorrow and this will help thanks
it would be so cool if you made versions of the videos with all the vector calculus involved
If I'll ever feel useless, I'll remember there's people who dislikes this video
0:56 WORK IS MAD 🤣🤣🤣😂
Delivery is quite stiff, but I love your format and exceptionally clear writing. Thanks for making this!
He sticks to rigor and he's fun yet which is rather a rare combination. Only someone gifted can do something similar. Saludos desde la República Domincana!
Very nice explanation
2 questions:
1) Between step 2 and 3 of the answer for the comprehension, how did -1,539 *J* become -1,539*kg m^2/s^*?
2) Between step 3 and 4 of the answer to the comprehension, how did (11.2 m/s)^2 turn to 125.4 m^2/s^2?
Btw great video 👌😄
1) that's what joules are, N-m, and N are kg m/s^2
2) by squaring it
Wow I can’t believe I didn’t catch these simple things. Thank you so much, and also, thanks for answering so quickly. You’re a fricking legend
your good i hope you get 1 million subs
I wish I knew about you when I had to take Intro to Physics like 2 years ago. I would've gotten an A NOT a B! :( Oh, well ....understanding it is more important than a grade.
Grades follow
@@sayandkr4333 grades relegates. It's just a number after-all
Imagine being upset about a B.
@@FieldMarshalYT imagine being super relieved cuz you passed the subject with a D XD.
@@hunzalashahid4000 I can relate
Thanks ❤prof dave
this guy has saved us from at least 1 exam
Intro ... That's a great way to start a video
Thanks so much! This video was really helpful!
Thank you for explaining this! I was wondering why it was necessary to ascribe an object at rest "potential energy" when it hasn't moved and isn't necessarily going to. I was wondering why we can't just say it has energy when it's actually in motion. But the pulled arrow on a bow and compressed spring examples illustrated the point, and then the clarification that potential energy exists due to an object's position in a *field*, and often when we say potential energy we are talking about gravitational potential energy. I hope I understood that but that was my take away! Thanks!
Your video was short and helpful compare to other videos. I kinda got the material gradually. When I do the problem, I almost got it except the negative signs.
I wonder why is negative ?
same question
I want to know why as well:(
5 years late but its negative because the question states "1539J of energy is transferred" implying that its work done BY the system which is always negative like professor dave said earlier in the video
You are a god sent, thank you!
I wasn't careful enough so didn't take into consideration that W has to be negative. Just by the change of a sign I got my results = 13.674m/s. So just by the change of a sign I gained more energy after the impact x'D
I am doing masters in theoretical physics . i was studying about electrons EPE in a experiment but suddenly forgot about PE . i guess more knowledge you gain it gets all sort of messed up in head , it needs to be cleared out time to time 😂.
Keeping it simple, I discovered that all animate objects are Kinetic Energy & all inanimate objects are Potential Energy & only Kinetic Energy can become Potential Energy & not the other way around. ~Guadalupe Guerra
what a mad work :D
you are great sir . thanks a lot.
I'm thinking that the reason for W being negative is for a similar reason that exothermic reactions in chemistry are negative. They transfer or "release" energy into their surroundings, which is represented by a - sign. Idk if this is a proper way of thinking about it, or if it's even correct, but it worked for me so I'm kk with it.
I have the same question as well.
I cannot understand why it is a negative W
thank you so much sir !! your videos are short and clear. initially I hated physics but after seeing your videos I got clarity about concepts . Your doing great job.
Great explanation
Plz sir I so grateful for ur lesson and love it, it's more understandable. But plz sir can u illustrate ur calculation, I am finding it difficult to... Plz 🙏🙏🙏
awsome explanation
@prof Dave,
Just want to ask questions for clarification.
According to the Kinetic Molecular Theory "particles of matter constantly move". Kinetic Energy by definition is often defined as the energy of an object due to its motion. At a macroscopic level, we identify and differentiate Kinetic energy and Potential energy based on the observable motion of an object. Simply, if it's moving there is KE (energy in motion). Otherwise, PE.(energy at rest). However, at the microscopic level, as per the KMT, particles that make up matter move constantly, and this is where my understanding of KE and PE becomes a bit fuzzy: 1. Considering KMT - particles of matter are always in motion, does Potential Energy form really exist?
Hope you could give clarification on this.
On microscopic level all energies are either Kinetic or potential as they are either created due to motion or particle interaction.
This is the equation I came up with to solve for vf in the comprehension section at the end of the video. (2((w)+1/2(m)(vi^2))/(m))^(1/2)=vf What's wrong with my algebra? I'm extremely frustrated.
i want this teacher to my school
Hi im at 7th grade can you please explain about Mechanical energy?? Thank you so much dave 😊
What are the difference between kinetic energy and potential energy? I discovered that all animate objects possess kinetic energy, while all inanimate object exhibit potential energy. Kinetic energy can be transformed into a potential energy, but the reverse is not true. Additionally, potential energy remains constant, regardless of whether it is in motion or at rest. ~Guadalupe Guerra
thank you
it really helped thank you so much
I got full marks on objective test because of you
I find it easy to watch your explanation than reading too much notes
Potential energy ☀️
Thanks once again! Love your videos.
I have an interest in kinetic energy and I am looking for a definition as we as an example. I also think it should be broken down and simplify. I know that a ball sitting on the ground still has kinetic energy.
A ball sitting on the ground has zero macroscopic kinetic energy in the reference frame of the ground. If you look at it from a different reference frame, like the center of Earth, it will have kinetic energy as a consequence of moving with its immediate environment. It also has internal kinetic energy at the molecular level, as this is how objects store their thermal energy. Every object that isn't at absolute zero has internal kinetic energy.
Finally know the right answer now😊
Thankyou sir!
Man, and what about some explanation about the other types of Energy? ? ?, chemical, heat, solar, etc
wow my pshyc teacher gave us link to here
Our hero
Great video 😀👍💖
If you understood anything from 0 seconds to 1:15 you have to be one of Albert Einstein’s secret children
What is energy? What is origin of energy?
Energy is the ability to perfum,work or change an object.
Professor I think you forget to mention the relation of work with potential energy, I wonder if it’s work= change in potential energy
Wow man you are great
Done.
What if the other object's mass is greater
Professor Dave sir can you please describe the problem
FR BRO
Thank you!! very helpful!
Would someone please explain the difference in 'work done on a system' and work done by the system'??
1:01 holy cow
"after some simplification" lol, still seems hard to me
Wouldn't a ball in my hand have a kinetic energy force pointing towards my hand because it's exerting a force on my hand? Or is that called Potential Energy just because it's at rest?
Work = mad
Sounds about right
thank u
He knows a lot about the science stuff. It’s professor Dave explains. (Crying Sounds)
Why is the work in the comprehension in negative value?
"transfers" 1539 J energy to another object as work, so work is done "by" the system. Therefore, work has a negative value.
Can someone provide a more in depth explanation? I made the same mistake, I input the value for W as a positive integer. Please explain?
professor dave i should tell u this but u should had explain that kinectic energy as u did with potential energy . You explained the potential well but i ma bit confused in kinetic.
it's the energy an object possesses by virtue of its motion, just like i explain here! you can email if you have a specific question.
Oh no the W is mad
As velocity is relative,Is kinetic energy relative?
I don't understand how the gravitational potential energy can depend on height in this simple way. Suppose you take an object and increase its height by 100,000,000 kilometers; does such an object have more potential energy or less than an object at 10 meters above the ground? The object at 10m will experience much greater acceleration because the object at 100,000,000 km is so far away and thus experiences a much weaker gravitational field. Does the definition assume a uniform gravitational field throughout space?
As velocity is frame dependent, is kinetic energy also frame dependent?
ur a legend
Is there any chance that Kinetic energy and Potential energy are equal at a height?
Would be nice if you kept your terms constant, initially you're using 1/2mvf^2 and later on in the comprehension check it is marked as 0.5mvf^2... Very confusing when you're learning! :D
Work = force x distance? I thought it was Work = force x DISPLACEMENT.
4:05 Why is the 1,539 J is negative?
energy transferred out of the object
I have a question. In the part of the work-kinetic energy theorem, you said that when the work is negative, the system is doing a work, but in my opinion, the force is doing a work that makes that the kinetic energy of the particle decreases, and this work can be computed as the subtraction between final kinetic energy and initial kinetic energy of the system.
What do you think?
When net work is negative, this means work is leaving the kinetic energy of the object we are studying, and the object decreases its speed. This could mean energy is being stored in the form of potential energy, or it could mean a non-conservative force such as kinetic friction is converting the energy into heat and taking energy out of the mechanical domain.
Potential energy is a shortcut to calculate the work done by conservative forces, because it is a state function instead of a path function. It only depends on initial and final states, rather than the details of the path. When we exclude forces associated with a potential energy, and only study the non-conservative forces, the work-energy theorem changes from "KEfinal = W + KEinitial" to "KEfinal + PEfinal = KEinitial + PEinitial + Wnc". The sum total of PE+KE is what we call the mechanical energy; i.e. the energy we can exchange reversibly through the mechanical actions of the system. Wnc is the work of non-conservative forces. Such as work done by human forces to initiate the energy of the system, or work dissipated as heat by frictional forces, or work done on a human as human forces guide the system to rest. Any force that can add or subtract energy to an object in motion, for which we don't track a potential energy.
@@carultch Great explanation. I know you're responding to someone else but that's still very helpful for me, thanks xD!
@@ryankuykendall8303 Always happy to help.
@@carultch so does that explain why 1539 is negative because it is leaving the Kinetic Energy of the object?
@@michdawnespera9578 Yes. If kinetic energy is decreasing, that means the net work being done on the object is negative. Is there a specific issue I could help clarify, that I'm not seeing in your question?
Using this information for martial arts purposes
This question may seem dumb but Why's the work = - 1539 J negative?
Work done is negative when the force acts opposite to the direction of displacement.
I understand this except for the math at the end. I get why those values plug into the equation the way they do, and I know that joules is kg m^2 / s^2 in SI base units. After that I'm stuck - I can't see how the equation has been simplified and rearranged. Help please Prof. Dave! Loving your videos btw
so first we just multiply 50 kg by 0.5 in both terms on the right side to get 25 kg, and then we factor 25 kg out of the binomial to get 25 kg times that reduced binomial then when we divide both sides by 25 kg we lose kg on the left, ending up with m^2/s^2, we add the other m^2/s^2 term from the right side, and when we take the square root its m/s! if this is still tricky, i suggest watching lots of my math tutorials!
+Professor Dave Explains Thanks Professor Dave. It's a long time since I studied maths at school so I'm a bit rusty, so yeah I will have to watch some of your maths videos. (Yes "maths" with an s - that's how we say it here in the UK :) )
Got it