An elevator is being pulled up from the ground floor to the third floor by a cable. The cable is exerting 4500 newtons of force on the elevator. According to Newton's law of action-reaction, what is the gravitational force on the elevator, in newtons, if the elevator is NOT accelerating?

The gravitational force on the elevator, if the elevator is NOT accelerating is 4500 N.

Given data:

The magnitude of force on the elevator is, F = 4500 N.

From Newton's third law of motion, the action of the cable force is equal to the reaction of the gravitational force on the elevator which is the weight, W and motion of the elevator as follows,

F = W + ma

Here, a is the acceleration of the elevator. Since, the elevator is not accelerating. Then, a = 0 .

The weight of the elevator is due to the gravitational force. So, we need to obtain the weight as gravitational force.

Solving as,

Thus, we can conclude that the gravitational force on the elevator, if the elevator is NOT accelerating is 4500 N.

Learn more Newton's third law here:

link

The gravitational force on the elevator = 4500N

Explanation:

The given parameters are;

The force applied by the elevator, F  = 4500 N

The acceleration of the elevator = Not accelerating

From Newton's third law of motion, the action of the cable force is equal to the reaction of the gravitational force on the elevator which is the weight, W and motion of the elevator as follows;

F = W + Mass of elevator × Acceleration of elevator

∴ F = W + Mass of elevator × 0 = W

F = 4500 N = W

The net force on the elevator is F - W = 0

The gravitational force on the elevator = W = 4500N.