rudransh verma said:
That formula is only valid if ALL is the moving object's kinetic energy is converted to potential energy at the highest point (height h). It can be derived from ##\frac 1 2 mu^2 = mgh##.
But in the current problem,
some of the moving object's kinetic energy is transferred to another object. So the above formula is not useful here.
Don’t use a formula unless you understand the context in which it is valid.
rudransh verma said:
I have not read about conservation of momentum. I believe it says Total Momentum before and after the collision is constant.
That's right.
Let’s assume the question is as described in Post #4.
This is what happens:
When the moving block (initial velocity u) and stationary wedge meet, the block will slide up the wedge and also the wedge will accelerate.
For some value of u, the block will
just reach the top of the wedge. At this instant, the block and wedge will have the have same velocity, say v.
Here is an outline of what you must do.
Using the conservation of momentum. calculate v in terms of u, m and ##\alpha##.
If you haven’t learned about conservation of momentum for simple ‘collisions’ you need to read-ahead and/or watch a YouTube video or two.
After you have an expression for v, you can use conservation of energy to find u in terms of m, ##\alpha##, h and g.
Post your attempt, showing
all your working.
Edit. This Post overlaps
@vcsharp2003's Post #11, but since I've already written it, here it is.