Hi Trojan. Good question. One way would be to apply the 50N force to the large block and measure the acceleration achieved. If friction was present the acceleration would be less than the 1m/s2 that was calculated. If you measured the actual acceleration achieved you can calculate the force that was accelerating the block from F=ma. The difference between this calculated force and the 50N applied force is the friction force. Mac
Hi Oshyrath. When using equations it is important to define what the variables are. Your point is that in Newton's Second Law of Motion the force we refer to should be the net force. This is calculated by summing the forces on the body under consideration remembering that the direction of the force must be taken into account during this summation. As long as we define F in F=ma as the net force then it is OK to use F=ma. You can also express the equation as you have suggested. Regards Mac
Thank you Sara for letting me know. I'm pleased you found it helpful. I am currently preparing a video on the third law which will be released in the near future. I am interested to know how your teacher used it as part of the lesson? Was it shown to everyone at the same time or part of individual study activity? Regards Mac
The symbol is used to indicate the summation of the forces. It is the upper case letter Sigma from the Greek alphabet. We use this symbol as a quick way to indicate summation when writing equations. Mac
Hi Vonti, I understand why it is confusing. The reason the time is squared is: Velocity is defined as a distanced travelled per unit time. Hence the use of m/s. Acceleration is a change in velocity per unit time. Hence we have change in velocity (m/s) per unit time (s). So acceleration is m/s/s which is m/s^2. For constant acceleration the distance travelled changes with the square of the time. You calculate this using the equation distance= 0.5at^2 assuming the initial velocity is zero. Mac
Hi Jason, thanks for your comment. You are right. If the acceleration is zero then it tells us that the forces are in balance. The reason for the exercise was to demonstrate how to use F=ma to calculate acceleration. In the case of the block on the table it is zero. We would use the same analysis approach to calculate a non zero acceleration for the situation where an unbalanced force was active. The zero acceleration case is a good check since it is an obvious result. Regards Mac
Hi Amie. It is good that you are thinking carefully about the direction of the force since this is important when analysing forces. If you pull an object towards you it will move towards you since it moves in the direction of the pull force. Similarly if you push the object away, it will move away from you as it moves in the direction of the push force. Have I understood your question correctly? Regards Mac.
Shubhom, Sorry I can't reply directly to your question as I don't think you have enabled the option on your account to receive comments. The object will only accelerate while a net unbalanced force is applied. So if you push the block it will accelerate while the push is active on the object. As soon as you stop pushing it the block will no longer accelerate. It will continue to have velocity but not acceleration. Mac
Hi Nicolaus. You have good instinct here. However the quantity you are discussing is energy - kinetic energy to be precise. In both cases you have the same car moving with the same velocity and this means it has the same kinetic energy which is defined as 0.5 times mass times velocity squared (similar to what you are suggesting). Acceleration relates to how quickly it achieved this velocity. The larger the acceleration the larger the force required for a given mass of car hence F=ma. Mac
Hi Maria, Thanks for your feedback. I'm pleased you found it helpful in your studies. I'm also pleased that you can understand my Scottish accent. I had a good friend who lived in Poland and he sometimes found my accent difficult to understand when talking by phone. Regards Mac.
I had a hard time understanding Newton's 2nd Law of Motion during lecture. The way you were able to simplify everything really helped. Thanks for uploading the awesome video Mac!
Hi Hugo, thanks for your comment. You have identified a very important point about using Newton's second law. The force in F=ma is the sum of the forces on the object in a given direction. So vertically you have 49N down (for a mass of 5kg) and 49N up from the table on the block (due to the table supporting the block). The sum of these forces (including their direction) is 49-49=0. See my video on Newton's third law to understand why the table exerts the 49N on the block. Regards Mac
Hi Stafus. You make a good observation. The reason they can move like that on the moon is that the gravitational force on the moon is only approximately 17% of that on earth. Everything weighs less. Not only the suit but also the astronaut. His leg can still generate the same force so the net force upwards (remember to sum the forces) as he jumps is much greater than on earth. The astronaut can therefore jump higher and has a lower acceleration down to the surface than on earth. Mac
Hi Bobby, I can't reply to you directly as you don't have that option selected on your account. Thanks for letting me know about your test result. Well done. Mac
Hi Evan, it has a similar form to F=ma but uses different terms. As an exercise try searching for rotational motion and see if you can find the equation. Mac
Stafus, I assume you mean the upwards acceleration. The inertial mass doesn't change on the moon. What has changed however is the net upwards force on the astronaut and the suit. You need to sum the gravity force and the leg force. So a=F/m will give a higher acceleration for the same mass due to the higher net force. You can't ignore gravity here as it is a force acting on the system and will affect the net force and hence acceleration.
Well this is better than e-learning websites . Please upload more of these videos I have just one complain to make - the messages which tell us to like and subscribe appear in between the video which disturbs my concentration .
Hi Guerras thank you for your comment. I understand there is a debate about forces. The aim of these videos is to help students learn about currently accepted concepts. Once students are confident with the concepts they are then able to engage with the more subtle discussion that you have mentioned. I personally find the use of the equation F=ma an effective way to solve engineering problems due to its simple form and accuracy in describing physically observed behaviour. Regards Mac
Thank you for this video very much appreciated, you see I come from Poland and English is my second language and although I lived in Great Britain for over 3 years I am still sometimes struggling with understanding the teachers. This was a lot easier for me to understand, very helpful :) Thanks again Maria
Thank you so much for uploading this video! It helped me visualize what was happening which helped me understand the concept better. I look forward to your future uploads. :D
hi mac.....igot a got a doubt..if.. F=m(v-u)÷t...here 't' is showing the time where the force is applied on the object continuesly or it is the time that helps as a reference to determine the 'v'????... in other words...does force needs to be applied continuesly throughout the time or just one push at the start is sufficient to produce accelaration
Thanks you for your answer. So when physicists are talking about force they are talking about the RESULTS of kinetic energy being applied to an object? Would a more descriptive and long winded explanation in layman’s terms of newton’s second law be: “the result of an object (aka mass) colliding with another object causes the other object to speed up and/or change directions.” So force is the measure of power after the collision and kinetic energy is the measure of power before the collision?
Thanks EaszAz. Often the hardest thing is to be first to understand something - even harder to explain it in simple language. Newton did a good job in this regard. The laws are easy to state but have a great deal of significance. We can use them to explain what is happening all around us and use our understanding to design and develop new products to enhance our lives. Mac
Hi Bareerah, I am preparing the video of the third law now. However, since it takes a significant time to create these videos it won't be ready for a few months. You can see screen shots of the video as it progresses at my website. Regards Mac
Hi Mac, very explaining video. I'm just wondering. Since the cube was moving 1/ms (meters per second) how come the distance the cube travels increases for every second that passes? It looks like the Meter per second increases for each second. Please explain.
Hi Daniel, you are correct. The distance is increasing because the block is accelerating at (1 meter per second) per second. This means the velocity is increasing every second by 1 meter per second. You thought the block was moving with a constant velocity of 1 meter per second but it was actually accelerating so the velocity is not constant. This means that it will travel further each second due to the increasing velocity. Mac
another interesting thing you can do here is demonstrate newtons third law. What would happen if you connect the spring to the box and held down the box while moving the arm spring to the right until it measures say 5 newtons, then release the box and the spring. what would happen? the arm and the box both would probably move towards each other, demonstrating reaction forces.
I also find it much easier to understand when I can visualise the concept. That's one of the reasons I produce my animations. Thanks for your feedback iLearning. Mac
I'm confused about why the acceleration is squared? Does this mean that the distance travelled is squared every second? Please could you explain how the distance over time at each second interval is calculated. A tape measure on the animation would be really helpful.
Hi Mac, Why does the block seem to move in the same direction as the force is applied? Shouldn't the force have pushed the block in the other direction?
Hi Amber, Thank you for your feedback and I'm pleased you liked it. I have just released my new video on Newton's third law and I am in the process of planning my next video. I will take your request into consideration. Mac
![Newton's 2nd Law of Motion in Physics Explained - [1-5-6]](http://i.ytimg.com/vi/5T_O6Zt5Xt4/mqdefault.jpg)
![Newton's 2nd Law of Motion in Physics Explained - [1-5-6]](/img/tr.png)
![BLACK BAG - Official Trailer [HD] - Only in Theaters March 14](http://i.ytimg.com/vi/Du0Xp8WX_7I/mqdefault.jpg)
Hi Trojan. Good question. One way would be to apply the 50N force to the large block and measure the acceleration achieved. If friction was present the acceleration would be less than the 1m/s2 that was calculated. If you measured the actual acceleration achieved you can calculate the force that was accelerating the block from F=ma. The difference between this calculated force and the 50N applied force is the friction force. Mac
Hi Oshyrath. When using equations it is important to define what the variables are. Your point is that in Newton's Second Law of Motion the force we refer to should be the net force. This is calculated by summing the forces on the body under consideration remembering that the direction of the force must be taken into account during this summation. As long as we define F in F=ma as the net force then it is OK to use F=ma. You can also express the equation as you have suggested. Regards Mac
Thank you Sara for letting me know. I'm pleased you found it helpful. I am currently preparing a video on the third law which will be released in the near future. I am interested to know how your teacher used it as part of the lesson? Was it shown to everyone at the same time or part of individual study activity?
Regards
Mac
The symbol is used to indicate the summation of the forces. It is the upper case letter Sigma from the Greek alphabet. We use this symbol as a quick way to indicate summation when writing equations.
Mac
Hi Vonti, I understand why it is confusing. The reason the time is squared is: Velocity is defined as a distanced travelled per unit time. Hence the use of m/s. Acceleration is a change in velocity per unit time. Hence we have change in velocity (m/s) per unit time (s). So acceleration is m/s/s which is m/s^2. For constant acceleration the distance travelled changes with the square of the time. You calculate this using the equation distance= 0.5at^2 assuming the initial velocity is zero. Mac
that accent took me off guard so much
Indian accent
Scottesh
JazziHD Ireland’s
Thank you so much Mac..I understood very well the concept of second law....
Hi Jason, thanks for your comment. You are right. If the acceleration is zero then it tells us that the forces are in balance. The reason for the exercise was to demonstrate how to use F=ma to calculate acceleration. In the case of the block on the table it is zero. We would use the same analysis approach to calculate a non zero acceleration for the situation where an unbalanced force was active. The zero acceleration case is a good check since it is an obvious result. Regards Mac
Hi Amie. It is good that you are thinking carefully about the direction of the force since this is important when analysing forces. If you pull an object towards you it will move towards you since it moves in the direction of the pull force. Similarly if you push the object away, it will move away from you as it moves in the direction of the push force. Have I understood your question correctly?
Regards Mac.
Thank you for your feedback Eman. I'm pleased you like them.
Regards Mac
I appreciate the huge amount of work that has gone into this video- congratulations.
Thank you Mac this was very helpful. I got a 100 on my test thanks to you! ;) just wanted to say thanks.
How life my guy
Congos
Thank you sir for the reply and the clarity , conveinced almost
there should be more of these videos! i love them!
Thanks for your feedback Manik. I will look at the message and see if I can move it to a less distracting time during the video. Mac
Shubhom, Sorry I can't reply directly to your question as I don't think you have enabled the option on your account to receive comments. The object will only accelerate while a net unbalanced force is applied. So if you push the block it will accelerate while the push is active on the object. As soon as you stop pushing it the block will no longer accelerate. It will continue to have velocity but not acceleration. Mac
>> net unbalanced force i
Well done
Hi Nicolaus. You have good instinct here. However the quantity you are discussing is energy - kinetic energy to be precise. In both cases you have the same car moving with the same velocity and this means it has the same kinetic energy which is defined as 0.5 times mass times velocity squared (similar to what you are suggesting). Acceleration relates to how quickly it achieved this velocity. The larger the acceleration the larger the force required for a given mass of car hence F=ma.
Mac
Thank you for this video! It helped me understand Newtons second law of motion much easier.
I got a 100 on my physics test thanks to this I love u
Well done Naram.
Mac
This is very informative! I plan to show this to my high school students to increase understanding!
Great video.
Important from the outset to state that the f in f=ma is the Resultant or unbalanced Force on an object.
Thanks for your help.I will come with more questions on physics.
Thanks Dias. I will take your suggestions into consideration as I plan the next video.
Regards, Mac
Thanks alot mac, really helpful while im studying for exams. Really appreciate it.
This is amazing, it's much clearer than my text books :D Thank you
Hi Pescarlerik. Thanks for your feedback. Yes I am originally from Glasgow area and studied at Glasgow University.
Mac
:) I slept through class and thanks to this video I understand the lesson I missed today :)
Great video thankyou .
I really understood the Newton second law.
Hi Maria, Thanks for your feedback. I'm pleased you found it helpful in your studies. I'm also pleased that you can understand my Scottish accent. I had a good friend who lived in Poland and he sometimes found my accent difficult to understand when talking by phone. Regards Mac.
I had a hard time understanding Newton's 2nd Law of Motion during lecture. The way you were able to simplify everything really helped. Thanks for uploading the awesome video Mac!
seanbarrett503 Thanks for your feedback Sean.
This is so helpful. Thanks a lot, Mac!
Hi Hugo, thanks for your comment. You have identified a very important point about using Newton's second law. The force in F=ma is the sum of the forces on the object in a given direction. So vertically you have 49N down (for a mass of 5kg) and 49N up from the table on the block (due to the table supporting the block). The sum of these forces (including their direction) is 49-49=0. See my video on Newton's third law to understand why the table exerts the 49N on the block. Regards Mac
Hi Bareerah, I will be preparing the video on the third law in the near future.
Regards Mac
I'm pleased you found it helpful Alma.
Mac
Hi Stafus. You make a good observation. The reason they can move like that on the moon is that the gravitational force on the moon is only approximately 17% of that on earth. Everything weighs less. Not only the suit but also the astronaut. His leg can still generate the same force so the net force upwards (remember to sum the forces) as he jumps is much greater than on earth. The astronaut can therefore jump higher and has a lower acceleration down to the surface than on earth.
Mac
good stuff, do more,I got an A star for my exam on forces:)
+Abisai Yogarajan Thanks for you feedback. Good job on your exam results. Mac
Hi Bobby, I can't reply to you directly as you don't have that option selected on your account. Thanks for letting me know about your test result. Well done. Mac
Hi mike I like how explain 2nd law
Learnwithmac is the best
Thank you for the explanation, professor. (: Loved the video and hope you make more!
Thanks!! this makes a great help on understanding law of acceleration!
Thank you Mac! This video is very helpful to students like me.
Thanks for your feedback Albert.
BEST VIDEO EVER WATCHED!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!CONCEPT CLEARING VIDEO
+Sanjay Verma Thanks for your feedback Sanjay
Hi Evan, it has a similar form to F=ma but uses different terms. As an exercise try searching for rotational motion and see if you can find the equation.
Mac
Tanks for your explanation, it is really the best on the internet.
Stafus, I assume you mean the upwards acceleration. The inertial mass doesn't change on the moon. What has changed however is the net upwards force on the astronaut and the suit. You need to sum the gravity force and the leg force. So a=F/m will give a higher acceleration for the same mass due to the higher net force. You can't ignore gravity here as it is a force acting on the system and will affect the net force and hence acceleration.
Thanks for the feedback Beshoo. I'm glad you found it helpful. Mac
useful for students
Well this is better than e-learning websites . Please upload more of these videos
I have just one complain to make - the messages which tell us to like and subscribe appear in between the video which disturbs my concentration .
Koen, I use the open source program called Blender. The link to the site for download is shown in the credits at the end of my video.
Mac
Whos that
Its so amazing, I'm gonna use your video learning as my teaching source
Thanks for your feedback Muhammad.
Mac
@singaporeoracherd Thanks for your feedback. I'm pleased you found it helpful and I wish you every success in your studies.
Regards Mac
Thanks for your feedback K.
Mac
Nice explanations. Now I'm clear about force, mass and acceleration. Thank you Mac.
Thanks for your feedback Abdur. Regards Mac
Excellent presentation and easy to follow. I am looking forward to your other videos. Thanks for making it.
Hi Guerras thank you for your comment. I understand there is a debate about forces. The aim of these videos is to help students learn about currently accepted concepts. Once students are confident with the concepts they are then able to engage with the more subtle discussion that you have mentioned. I personally find the use of the equation F=ma an effective way to solve engineering problems due to its simple form and accuracy in describing physically observed behaviour. Regards Mac
very good video presentation it entertain yourself and you can learn more how did you do that thing Professor Mac?
Hi Rogelio, thanks for your comment. Have a look at my blog to see how I create the animations. Here is the link: www.learnwithmac.com
Hi Evan, I don't understand your question. What do you refer to when you say revolutions? Revolutions of what?
Mac
Nice explanation
Thanks a lot! This really helped me with a project I'm doing!
I Likd it. My doubts are all cleared, But what is Linear Momentum??
Please answer...
So clear and concise, thanks Mac!
David Gordon Thanks for the feedback David.Mac
Hi
I am trying to learn for a science test and this helping me study thank you so so much!!
youaretheonlyone Thanks for your feedback. Best of luck in your test. Regards Mac
Thank you for this video very much appreciated, you see I come from Poland and English is my second language and although I lived in Great Britain for over 3 years I am still sometimes struggling with understanding the teachers. This was a lot easier for me to understand, very helpful :)
Thanks again Maria
Thank you for this very clear and informative demonstration.
Thanks for your feedback Jan.
Mac
Absolutely amazing! Thank You very much for this information! This was explained much better than my prof explained it.
🤣
This video help me a lots to understand more about the 2nd law of motion thank you so much
Thanks for your comment Eurika. I'm pleased you found it helpful.
Mac
Thank you so much for uploading this video! It helped me visualize what was happening which helped me understand the concept better. I look forward to your future uploads. :D
hi mac.....igot a got a doubt..if.. F=m(v-u)÷t...here 't' is showing the time where the force is applied on the object continuesly or it is the time that helps as a reference to determine the 'v'????... in other words...does force needs to be applied continuesly throughout the time or just one push at the start is sufficient to produce accelaration
Just what I thought for decades . Acceleration needs a constant increase in force in order to cover larger distances in the same time . Right ?
Awesome professor Mac beautifully explained, easily understood!!!!!!!!
Thank you Mac. Your videos are the best!
Thanks you for your answer. So when physicists are talking about force they are talking about the RESULTS of kinetic energy being applied to an object? Would a more descriptive and long winded explanation in layman’s terms of newton’s second law be: “the result of an object (aka mass) colliding with another object causes the other object to speed up and/or change directions.” So force is the measure of power after the collision and kinetic energy is the measure of power before the collision?
Thanks a lot prof Mac
Thanks EaszAz. Often the hardest thing is to be first to understand something - even harder to explain it in simple language. Newton did a good job in this regard. The laws are easy to state but have a great deal of significance. We can use them to explain what is happening all around us and use our understanding to design and develop new products to enhance our lives. Mac
Thanks alot Mac.... You really helped alot explaining the second law..!!
+Stephan van Zyl Thanks for your feedback Stephan. I'm pleased you found it helpful. Mac
Thanks for the feedback.
Mac
Well done !!! best explanation i have seen
Hey Mac, will you please talk me through calculating tension on a smooth horizontal plane?
It seems he never replied
@@philmccrack9862 😂😂😂 I can't even remember watching this. Got a maths degree out of it though
Hi Bareerah, I am preparing the video of the third law now. However, since it takes a significant time to create these videos it won't be ready for a few months. You can see screen shots of the video as it progresses at my website.
Regards Mac
very clear illustration
Thanks for your feedback Senen. I'm pleased you found it easy to understand. Mac
a very good video. thanx mac...............................
+Hasindu Ranasinghe Thanks Hasindu. Mac
Excellent teacher! Unfortunately my physics teacher doesn't really explain things well. But I learn so quickly from watching your videos!
Hi Mac, very explaining video. I'm just wondering. Since the cube was moving 1/ms (meters per second) how come the distance the cube travels increases for every second that passes? It looks like the Meter per second increases for each second. Please explain.
Hi Daniel, you are correct. The distance is increasing because the block is accelerating at (1 meter per second) per second. This means the velocity is increasing every second by 1 meter per second. You thought the block was moving with a constant velocity of 1 meter per second but it was actually accelerating so the velocity is not constant. This means that it will travel further each second due to the increasing velocity. Mac
plzzz make videos on strength of material and thermodynamics and fluid mechanics and hydrolycis
Thanks for the feedback Joe.
Mac
learned a lot from this, thanks mac
Thanks for your comment. Mac
Nice work,Professor....
Everyone is probably here for a homework but I'm here because my teacher isn't good at explaining and I have a quiz in about 15 hours
another interesting thing you can do here is demonstrate newtons third law. What would happen if you connect the spring to the box and held down the box while moving the arm spring to the right until it measures say 5 newtons, then release the box and the spring. what would happen? the arm and the box both would probably move towards each other, demonstrating reaction forces.
Thank you!!
thanks. very useful information and nice presenting.
Also your video was excellent hope you make more
I also find it much easier to understand when I can visualise the concept. That's one of the reasons I produce my animations. Thanks for your feedback iLearning.
Mac
THANK YOU SO MUCH U SHOULD MAKE MORE VIDEOS YOU ARE A GREAT TEACHER GOD BLESS YOU
+Mary Lu Thanks Mary.
I'm confused about why the acceleration is squared? Does this mean that the distance travelled is squared every second?
Please could you explain how the distance over time at each second interval is calculated. A tape measure on the animation would be really helpful.
Wow. I'am really thankful for this video. We are now studying now this second law. Upload more please.! How to solve some of the problem.
Thanks for your comment Joshua. I should be releasing a new video explaining the concept of Force in the next few weeks.
Regards, Mac
I will wait for that. Thank you Professor Mac
You're so much better than my science teacher,thank you。
Nice animation good work
Hi Mac,
Why does the block seem to move in the same direction as the force is applied? Shouldn't the force have pushed the block in the other direction?
Very informative video. Thanks for sharing.
+Diane Blackford Thanks for your feedback Diane. Mac
Hi Amber, Thank you for your feedback and I'm pleased you liked it. I have just released my new video on Newton's third law and I am in the process of planning my next video. I will take your request into consideration.
Mac