Question

A 13.2kg block is on a ramp, with an incline of θ (a) If the ramp is frictionless what is the magnitude of the acceleration of the block down the ramp? (b) If the ramp has a coefficient of static friction of µs = 0.3, at what angle θ will the block start to move? Imagine like the friction lab, you slowly increase the incline of the ramp. (c) Does the angle found in b) depend on mass? (d) What is the work done by the Normal force on the block if it travels 1.00m down the ramp?

Answer 1

a) acceleration of the block: a=gsinθ

Where g=gravitational acceleration.

b) The condition for the block just to start moving is given as:

tanθ=µs=0.3

>> θ=tan^-1(0.3)=16.69°≈16.7°

c) No, the angle found in (b) does not depend upon the mass of block. It only depends upon the coefficient of static friction between the block and ramp surface.

d) We know that the normal force acts perpendicular to the displacement-direction so the work done by normal force will be zero.