Height of a Ball on a Moving Wedge: How Does the Angle Affect the Result?

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AI Thread Summary
The discussion centers on determining the height a ball reaches on a wedge, examining two scenarios: a fixed ramp and a movable ramp on a frictionless surface. For the fixed ramp, the height is calculated using energy conservation, yielding h = v²/2g. In the case of the movable ramp, the ball imparts a force on the wedge, causing both to accelerate, necessitating the use of conservation of momentum alongside energy conservation. The angle of the wedge significantly affects the force exerted by the ball, influencing the overall dynamics of the system. Understanding these relationships is crucial for solving the problem accurately.
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Homework Statement


a ball with mass m and velocity v is moving up a wedge of mass M. What height does the ball reach if:
a) the ramp is fixed on the table
b) the ramp is able to move on a frictionless surface


Homework Equations


mgh
(1/2)mv(squared)


The Attempt at a Solution


for a) i just solved for h using both equations given above, since there is a loss in kinetic energy which is converted to a gain in gravitational potential energy as the ball moves up the wedge. so this gives me that the h = v(squared)/2g.
im stuck on b) however.
 
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If the ramp is supported by a 'frictionless' surface, then as the ball of mass m goes up the ramp, it imparts a force on the ramp, and that force is related the weight.

So now the ball of mass m is doing work on the ramp of mass M, and both accelerate.

Think about using conservation of momentum in addition to conservation of energy.
 
well that was sort of my train of thought as well. the ball will exert a force onto the wedge thus making both move.
we know that v'2 (that is the new velocity of the wedge with mass M) = (2M/m+M) * v1 (that is the original velocity of the ball)

but I am confused because isn't the angle a factor aswell, i mean the force exerted on the wedge by the ball is different depending on how steap it is.
i mean taken the extreme case we could say the wedge is in fact block, in that case i can see the conservation of momentum as given above applying to this situation, but in a case where the angle is flat the force exterted on the wedge would be less, or at least that's what I am thinking.
 
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