Ablock is moving at constant speed due to a horizontal force pulling to the right. the coefficient of kinetic friction, hk, between the block and the surface is 0.20 and the mag- nitude of the frictional force is 100.0 n, what is the weight of the block? (a 400 n (b) 600 n (c) 500 n (d) 267 n

c) 500 N

Explanation:

If the block moves with constant speed there is no acceleration. We draw a free body diagram and define the forces on the body.

The equation for the frictional force is:

Where is the kinetic friction coefficient. We write the equilibrium equation in the y direcction:

We replace this result in the equation for the frictional force:

We replace the data given by the exercise and find the weight

the part of the wave he is travelling on is the crest

e/c, where e is its total energy