An object with a mass of # 8 kg# is on a ramp at an incline of #pi/8 #. If the object is being pushed up the ramp with a force of # 4 N#, what is the minimum coefficient of static friction needed for the object to remain put?
Here downward component of the weight of the object tends to pull it down along the ramp.
It's value is
So,static frictional force must act by that amount upwards,such that the net force acting on the object will be zero.
Now,here maximum value of frictional force that can act is
So,we can write,