Question

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 and the people in it, in newtons, if the elevator is not accelerating?

Record your answer and fill in the bubbles on your answer document. Be sure to use the correct place value.

Answer 1

The gravitational force on the elevator = 4500N

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.

Answer 2

The gravitational force on the elevator = 4500N

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.