Thanks for the video! I was wondering, to find the displacement of the boat downstream, why we wouldn’t use the boat’s velocity but instead use the velocity in the down direction?
In this case the boat must head north of East. The 14 m per second is at an angle to East and is hypotenuse of the triangle. The 8 m/s is the vertical side of the triangle and you want to find the horizontal side of the triangle which is directed due east
Thank you for your explanation. If the boat attempts to sail straight across the water at its maximum speed, how far down the shore will it drift due to the current? In this question do I use the same steps as your solving distance steps?
How Do I know which side is the resultant velocity? In a question like this A boat can travel at a max speed of 14 m/s in still water. It must travel due East across a 120 m wide river, which has a current flowing at 8.0 m/s South. The resultant velocity is not the hypotenuse so I can I tell which side?
I would highly appreciate your response, please. the below question is similar to one of your questions, but how do I relate the 200 seconds to the solutions steps? "Assume now that the boat wants to cross the river in exactly 200 seconds, and wants to reach a point on the far shore directly opposite the launch point. What is the magnitude and direction of the velocity vector the boat must have through the water? Please specify the direction by drawing a picture and labeling a relevant angle."
I never answer homework questions (or questions that are obviously given to you by an istructor). Thats not why they're given to you. The goal of the videos is to empower you to answer your own homework questions.
Hi. Thanks for all your wonderful videos. Request your help on a particular problem from Indian CBSE Board 11th std on relative velocity. In this, the situation is that rain is falling vertically at a certain velocity. A person is walking / riding at a certain velocity, holding an umbrella. The ask is to find the angle at which the umbrella has to be held. I found this problem fundamentally confusing. The rain direction is unlikely to be affected by the speed of the person / object moving on the road, so would it not be wrong to add these 2 vectors and find a resultant vector and then an angle and say that the umbrella has to be held at an angle. Kindly advise. Thanks.
why do you use the time taken from directly crossing the river and use it as the same time when the boat moves downstream? they didnt specify the length of the river so it should be wrong
in addition ,the speed of the boat should be higher since the boat speed combined with the river flow downstream would be equal to 7m/s. thus it should cover a much larger distance logically than it would if i crossed the river perpendicular to the current.
Q1 answer: The boat travels at a angle to the straight-across direction. But the motion can be thought of as involving two simultaneous motions - the across the river motion and the down the river motion. These two motions occur at the same time and involve the same amount of time.
Q2 Answer: The length of the river isn't specified but has nothing to do with the problem or the solutions. Rivers can be 100s of miles long. But the boat doesn't travel the entire length of the river in the time it takes to cross it.
@@7mood593 Q#3 answer: Here is where you seem to be missing some key videos that come before this one in our series on Vectors and Projectiles ... mainly the ones on adding vectors or adding right angle vectors. Put briefly, velocity is a vector, meaning in part that direction is an incredibly important part of its description. When adding vectors, one must take this direction into account. For right angle vectors like these, their addition is done via Pythagorean theorem. Applied here: 3^2 + 4^2 = answer^2. Math leads to 5 m/s. Confusion on your part should lead you to another video on vectors and adding vectors. Hang in there - this stuff takes patience!
@@7mood593 If the boat was heading in the same exact direction as the current (downstream) then the speed would be 7 m/s like you said. But since the boat is oriented perpendicular to the current, we have to add the vectors perpendicularly too.
What if you're given the velocity of the boat in still water, plus the velocity of the water current down stream?. Please I need you to do a question of that format..... That's the only confusion I have now....Questions involving velocities of boats in still water... Thanks in advance
In the question that you've asked us to practice it ia given that it's the speed of boat with respect to the water. So the resultant velocity of the boat must be its velocity related to ground right? But why didn't we consider it that way. Could you please give an explanation.
The boat moves on water … called the speed of the boat with respect to water … or just boat velocity. The water moves along the ground … called the speed of the water with respect to the ground … or river velocity. The result of these two simultaneous is the boat moves relative to the ground … the resultant velocity.
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Thanks for the video! I was wondering, to find the displacement of the boat downstream, why we wouldn’t use the boat’s velocity but instead use the velocity in the down direction?
I could cry, I finally understand... Thank you so much this is the best video on this topic
Glad you got it. Come back for more.
In this case the boat must head north of East. The 14 m per second is at an angle to East and is hypotenuse of the triangle. The 8 m/s is the vertical side of the triangle and you want to find the horizontal side of the triangle which is directed due east
The best class ever I listened better than physics wallah
so clear
5:50
Thank you for your explanation.
If the boat attempts to sail straight across the water at its maximum speed, how far down the shore will it drift due to the current? In this question do I use the same steps as your solving distance steps?
Nope. The result of boat velocity + river velocity is a vector directed straight across the river.
How Do I know which side is the resultant velocity?
In a question like this
A boat can travel at a max speed of 14 m/s in still water. It must travel due East across a 120 m wide river, which has a current flowing at 8.0 m/s South.
The resultant velocity is not the hypotenuse so I can I tell which side?
I would highly appreciate your response, please.
the below question is similar to one of your questions, but how do I relate the 200 seconds to the solutions steps?
"Assume now that the boat wants to cross the river in exactly 200 seconds, and wants to reach a point on the far shore directly opposite the launch point. What is the magnitude and direction of the velocity vector the boat must have through the water? Please specify the direction by drawing a picture and labeling a relevant angle."
I never answer homework questions (or questions that are obviously given to you by an istructor). Thats not why they're given to you. The goal of the videos is to empower you to answer your own homework questions.
Hi. Thanks for all your wonderful videos. Request your help on a particular problem from Indian CBSE Board 11th std on relative velocity. In this, the situation is that rain is falling vertically at a certain velocity. A person is walking / riding at a certain velocity, holding an umbrella. The ask is to find the angle at which the umbrella has to be held. I found this problem fundamentally confusing. The rain direction is unlikely to be affected by the speed of the person / object moving on the road, so would it not be wrong to add these 2 vectors and find a resultant vector and then an angle and say that the umbrella has to be held at an angle. Kindly advise. Thanks.
why do you use the time taken from directly crossing the river and use it as the same time when the boat moves downstream? they didnt specify the length of the river so it should be wrong
in addition ,the speed of the boat should be higher since the boat speed combined with the river flow downstream would be equal to 7m/s. thus it should cover a much larger distance logically than it would if i crossed the river perpendicular to the current.
Q1 answer: The boat travels at a angle to the straight-across direction. But the motion can be thought of as involving two simultaneous motions - the across the river motion and the down the river motion. These two motions occur at the same time and involve the same amount of time.
Q2 Answer: The length of the river isn't specified but has nothing to do with the problem or the solutions. Rivers can be 100s of miles long. But the boat doesn't travel the entire length of the river in the time it takes to cross it.
@@7mood593 Q#3 answer: Here is where you seem to be missing some key videos that come before this one in our series on Vectors and Projectiles ... mainly the ones on adding vectors or adding right angle vectors. Put briefly, velocity is a vector, meaning in part that direction is an incredibly important part of its description. When adding vectors, one must take this direction into account. For right angle vectors like these, their addition is done via Pythagorean theorem. Applied here: 3^2 + 4^2 = answer^2. Math leads to 5 m/s. Confusion on your part should lead you to another video on vectors and adding vectors. Hang in there - this stuff takes patience!
@@7mood593 If the boat was heading in the same exact direction as the current (downstream) then the speed would be 7 m/s like you said. But since the boat is oriented perpendicular to the current, we have to add the vectors perpendicularly too.
What if you're given the velocity of the boat in still water, plus the velocity of the water current down stream?. Please I need you to do a question of that format..... That's the only confusion I have now....Questions involving velocities of boats in still water... Thanks in advance
The velocity of the boat in still water is what I call the "boat velocity" ... its how fast the boat would move if there were no current.
Thank you! This really clear things up for me
Glad it did.
In the question that you've asked us to practice it ia given that it's the speed of boat with respect to the water.
So the resultant velocity of the boat must be its velocity related to ground right?
But why didn't we consider it that way.
Could you please give an explanation.
The boat moves on water … called the speed of the boat with respect to water … or just boat velocity. The water moves along the ground … called the speed of the water with respect to the ground … or river velocity. The result of these two simultaneous is the boat moves relative to the ground … the resultant velocity.
Thank you!
How do I find the velocity of the water?
It's the velocity of the river
Thanks I need more examples
See the action plan at the end of the video. Sources of other example are described
tThank you!
Will you be adding rotational physics videos ?
No plans to do so.
1. Your car will serve as a boat. Write a brief statement to explain how boat's speed can be determined.?
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