# Wedge problem

because the normal force changes.
Why normal force changes?

haruspex
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Why normal force changes?
Because the accelerations of the wedge and block change, and because the angle changes.
A full analysis of the dynamics would be a bit of a challenge, and I suspect wll beyond what you are expected to do here. The question as posed is answered by the simple logic I've outlined. The wedge will be at max and min speeds when there is no horizontal force on it, and that will be when the block is at the lowest point. By momentum conservation, if the block is moving to the left relative to the wedge it will be the max, if to the right it will be the min.

• gracy
The wedge will be at max and min speeds when there is no horizontal force on it,
Because as long force is there ,acceleration will also be there and so velocity will go on increasing and there will not be any instant when we can say that it is maximum velocity that's why when there is no horizontal force no acceleration as well as deceleration ,at that moment velocity will be maximum and that is certainly the midpoint of depression.Right?One more thing
Velocity of wedge at mid point of depression is equal to velocity of wedge just before coming at mid point of depression when there was horizontal force acting on wedge.

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Please tell me my post #28 is correct or not?

haruspex
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Velocity of wedge at mid point of depression is equal to velocity of wedge just before coming at mid point of depression when there was horizontal force acting on wedge.
I don't understand. If the block is not at the middle of the depression then the speed of the wedge is changing.

Because as long force is there ,acceleration will also be there and so velocity will go on increasing and there will not be any instant when we can say that it is maximum velocity that's why when there is no horizontal force no acceleration as well as deceleration ,at that moment velocity will be maximum and that is certainly the midpoint of depression.Right?
Is this correct?

If the block is not at the middle of the depression then the speed of the wedge is changing.
But it must be having some instantaneous velocity just before coming to mid point of depression.

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haruspex
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But it must be having some instantaneous velocity just before coming to mid point of depression.
Yes... so?

But it must be having some instantaneous velocity just before coming to mid point of depression.
But it must be having some instantaneous velocity just before the block comes to mid point of depression.[/QUOTE]By it I mean wedge.

haruspex
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But it must be having some instantaneous velocity just before the block comes to mid point of depression.
By it I mean wedge.[/QUOTE]
I agreed the wedge would have some instantaneous velocity before the block reaches the mid point. But it will not be quite as much as when the block is at the mid point.

But it will not be quite as much as when the block is at the mid point.
Why?

haruspex
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Why?
Because as long as the block is not exactly at the mid point the normal force will have a horizontal component, accelerating the wedge.

Because as long as the block is not exactly at the mid point the normal force will have a horizontal component, accelerating the wedge.
That's why I have used the term just before coming at mid point.So that there will not be any horizontal force after that.

haruspex