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

what experimental evidence led scientists to change from the previous model to this one?

a few of the positive particles aimed at a gold foil seemed to bounce back.

the colors of light emitted from heated atoms had very specific energies.

experiments with water vapor showed that elements combine in specific proportions.

cathode rays were bent in the same way whenever a magnet was brought near them.