a man is trying to push a 200.0 kg chest of drawer at rest on the floor and the chest of drawers is 0.45. How much horizontal force must he exert on the chest of drawers to move it?

900 N

Explanation:

Assuming you have stated coefficient of friction is 0.45,

The normal reaction R of chest on floor is equal to its weight, so

R = mg = 2000 N

Frictional force is the opposing force for motion between two contact surfaces.

So when man try to push the chest, friction will come in to action and till the man overcome the friction the chest wouldn't move.

To calculate the maximum static friction F on the chest where coefficient of friction is 0.45 we get

F = 0.45R = 0.45*2000 = 900 N

So the required horizontal force is 900 N