# Homework Help: Quick easy question block sliding down wedge

1. Nov 28, 2012

### troytroy

1. The problem statement, all variables and given/known data
If a block is let go from the top of a wedge elevated at a certain angle and slides down will it reach the bottom at the same time as if the wedge was moving and then we let the block slide? so neglect friction and air resistance and basically just let the block slide down the wedge as it is at rest and while it is moving.

2. Relevant equations

3. The attempt at a solution
since the x and y components are independent of each other I assume that the block will take the same about of time to reach the bottom but just wanted someone elses input, thanks!

2. Nov 28, 2012

### Dick

Since this is a physics question, shouldn't you use some physics principles to answer it? If I get what you are asking, suppose the wedge is almost massless and the block is very massive. Then what?

3. Nov 28, 2012

### troytroy

All the question is asking about is about the time it takes a block slide down a wedge when the wedge is not moving at all and then how long it takes if the wedge is moving.

4. Nov 28, 2012

### Dick

No, it's not. If the wedge gets to move anyway it wants to then there is no particular answer. Anything is possible. I truely believe they want you to assume the the force exerted on the wedge by the block is what's making the wedge move.

5. Nov 28, 2012

### troytroy

I apologize I should have been much more clear about the problem. The problem started off as setting up a lagragian and the reason the wedge is moving is because of the energy from a spring that pushes it as soon as the block is released

6. Nov 28, 2012

### Dick

That's ok. But I still don't see that you've used any physics in your answer, much less a lagrangian. Could you do that?