Ice Cube Pressure on Incline: Solve for F

[brncsfns5621]

An ice cube, p = 917 kg/m^3, is sliding down a 16 degree frictionless incline. The sides of the cube each have a length of .75 m. What pressure does the cube exert on the incline?

P = F / A
= F / .75^3
= F / .42


F = ma
= 917 * a

I am having a problem figuring out the Force for this equation. I know it's simple, just can't put my finger on it. Please help.

 

[radou]

Which force is acting on the cube? One component of that force is in the direction of the motion of the cube, and one is perpendicular to the contact surface (m^2 !) of the cube and the incline.