# Need help (physics)

1. Sep 29, 2005

### bmore007

got it :) ................

Last edited: Sep 30, 2005
2. Sep 30, 2005

### PhysicsUSAAOK

Johnny jumps off a swing, lands sitting down on a grassy 20° slope, and slides 2.5 m down the slope before stopping. The coefficient of kinetic friction between the grass and the seat of Johnny's pants is 0.81, What was his initial speed on the grass?

3. Sep 30, 2005

### Tide

His speed down the slope will be

$$v = v_0 + (g \sin 20^o - \mu \cos 20^o) t$$

(a) Can you figure out where that came from?

(b) Can you use it to find the distance traveled?

(c) Can you determine the time at which he traveled 2.5 m?

(d) Can you guess my next question? ;)