normal force= m g cos 20
so
max static friction force = 0.2 m g cos 20
component of weight down slope = m g sin 20
Net force down slope = m g (sin 20 - 0.2 cos 20)
= m g (0.342 - 0.188)
that is positive so it starts sliding
then we need to use the kinetic friction
Net force now = m g (sin 20 - 0.15 cos 20)
= m g ( 0.342 - 0.141) = m g (0.201)
so
m a = m g (0.201)
a = 0.201 * 9.81 on earth approximately = 1.97 m/s^2
A slippery plastic block is resting in a ramp that makes an angle of 20 degrees with the horizontal. The coefficient of static friction between the block and ramp is 0.2. The coefficient of kinetic friction is 0.15.
A)will the block start sliding on its own
B)if you found that the block slid in part a, calculate its acceleration. If not, then calculate the minimum angle the ramp just have to start the block sliding
1 answer
1 answer