- #1
Peter G.
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I have some doubts concerning work, here are some examples I wanted to clear out:
So, when I kick a football, I am doing work on it. In this example the ball will be in contact with the ground throughout. It will slide over the floor.
The Energy Transfer: Chemical Energy from my muscles to Kinetic Energy of the ball.
And the distance through which the force is applied: Will be only the very short moment that my foot is in contact with the ball?
But what is the force against the work being done here? Friction at the moment of contact and application of force? And that would also be for a split second right? Because as the ball continued to roll it would still experience friction but no work is being done on it anymore. And can air resistance also be considered a counter acting force?
Now, I know how lifting a book works but I was wondering. What if I kick a ball upwards? Again, I’m assuming the force and the distance application is only during the moment of contact but my doubt is: In order to do work against gravity, am I doing work on the ball? Or did I do work on it, granting the ball Kinetic Energy and the football used its Kinetic Energy to do work against gravity?
And finally, can energy be transferred to different objects but in the same form? For example, when we ski down a mountain the skis deplete snow to the side. We posses kinetic energy and it is used to push the snow over a distance, giving it movement energy, or when we are playing pool and one ball hits the other, kinetic energy to kinetic energy again?
Sorry for the long text and I hope I made my doubts clear.
Thanks in advance,
PeterG
So, when I kick a football, I am doing work on it. In this example the ball will be in contact with the ground throughout. It will slide over the floor.
The Energy Transfer: Chemical Energy from my muscles to Kinetic Energy of the ball.
And the distance through which the force is applied: Will be only the very short moment that my foot is in contact with the ball?
But what is the force against the work being done here? Friction at the moment of contact and application of force? And that would also be for a split second right? Because as the ball continued to roll it would still experience friction but no work is being done on it anymore. And can air resistance also be considered a counter acting force?
Now, I know how lifting a book works but I was wondering. What if I kick a ball upwards? Again, I’m assuming the force and the distance application is only during the moment of contact but my doubt is: In order to do work against gravity, am I doing work on the ball? Or did I do work on it, granting the ball Kinetic Energy and the football used its Kinetic Energy to do work against gravity?
And finally, can energy be transferred to different objects but in the same form? For example, when we ski down a mountain the skis deplete snow to the side. We posses kinetic energy and it is used to push the snow over a distance, giving it movement energy, or when we are playing pool and one ball hits the other, kinetic energy to kinetic energy again?
Sorry for the long text and I hope I made my doubts clear.
Thanks in advance,
PeterG
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