particle on wedge

[markosheehan]

im stuck on question 8. the equation i got for the wedge is .6R -.5S=ma r stands for relative force of the particle s stands for relative force of the wedge . i got the equation 4mg-R=5m(.6a) for the particle where a stands for acceleration of the wedge. does anyone know where to go from here. are my equations wrong?. i drew a diagram of the forces

[Bender]

1) draw a free body diagram for both the wedge and the particle

2) write down the equations for X and Y for wedge and particle, now you have four equations with four unknowns (S, R, a_wedge and a_particle)

3) solve

[markosheehan]

were my first 2 equations right

[Bender]

The second isn't. You don't take the relative acceleration of the particle with respect to the wedge into account.

 

On closer inspection, the question seems to be missing information about the friction between wedge and particle. Ar you supposed to assume it is 0 then?