What is the normal force exerted by the ground on a 65-kg metal bar?
-640 N
640 N
-65 N

640N

Explanation:

Mass of a metal bar, m = 65 kg

We need to find the normal force exerted by the ground on the bar.

The normal force on an object acts in upward direction. The magnitude of normal force is equal to its weight.

N= mg

Put m = 65 kg and g = 9.8 m/s²

N = 65 × 9.8

= 637 N

or

N = 640 N

Hence, the normal force is 640 N.