Question

A block weighing `10 kg` is on a plane with an incline of `pi/6` and friction coefficient of `1/2`. How much force, if any, is necessary to keep the block from sliding down?

Answer 1

`6.65N`

Explanation:

Here downward component of weight of the block acting to pull the block down along the plane is `mg sin 30=10(1/2)g=5g`

And,frictional force acting upwards to balance that force is `mu mg cos 30=4.32g`(where, `mu` is the coefficient of friction)

So,net force acting on the object is `5g-4.32g=0.68g=6.65N` downwards along the plane,

So,this much force must be supplied to the block upwards along the plane to balance this extra force.