# Homework Help: Jumping on a sliding board with no friction between surfaces.

1. Jul 21, 2013

### judas_priest

1. The problem statement, all variables and given/known data

You stand at the end of a long board of length L. The board rests on a frictionless frozen surface of a pond. You want to jump to the opposite end of the board. What is the minimum take-off speed v measured with respect to the pond that would allow you to accomplish that? The board and you have the same mass m.

What is v?

2. Relevant equations

3. The attempt at a solution

Since there is no friction, on attempt of jumping, the skateboard is going to move back some distance. How do I find the distance and relate to the velocity? Clueless about this problem

2. Jul 21, 2013

### barryj

Just to be clear, I assume that you jump with a velocity and an angle with respect to the board, yes?

3. Jul 21, 2013

### haruspex

Suppose you take off at speed v, relative to the pond, and angle theta to the horizontal. What will be the vertical and horizontal components of your speed? How long will you be in the air? What horizontal speed did the board get? What then is your horizontal speed relative to the board?

4. Jul 25, 2013

sqrt(g*L/2)