Q10DQ - University Physics with Modern Physics

Question

A crate of books rests on a level floor. To move it along the floor at a constant velocity, why do you exert less force if you pull it at an angle above the horizontal than if you push it at the same angle below the horizontal?

Step-by-Step Solution

Answer

Due to less involvement of the frictional force, less force is needed to pull the crate above the horizontal.

Step 1: Significance of the force

The force exerted by an object is directly proportional to the mass and the acceleration produced by an object. The force is also directly proportional to the velocity of an object.

Step 2: Determination of the reason for exerting less force

As the force has been applied at an angle , the normal force significantly decreases. Moreover, with the decrease in the normal force, the kinetic friction force also decreases. Hence, the force exerted becomes smaller.

 

Thus, due to less involvement of the frictional force, less force is needed to pull the crate above the horizontal.