EIAT Forces, Torque, and Motion 5

Question 1

An elevator safety gear grips the guide rails to stop the car. The stopping force is an example of:

Accepted Answer

Friction force

Answer

Safety gear clamps the rail and uses friction to decelerate and stop the car.

Question 2

If a motor's output torque doubles while its rotational speed stays the same, what happens to its output power?

Accepted Answer

Power doubles

Answer

Power = Torque × angular velocity; doubling torque at constant speed doubles power.

Question 3

A 1,000 kg elevator car is at rest. What is the tension in the supporting rope? (g = 9.8 m/s²)

Accepted Answer

9,800 N

Answer

At rest (no acceleration), tension equals weight = 1,000 × 9.8 = 9,800 N.

Question 4

Which condition must be true for an object to be in rotational equilibrium?

Accepted Answer

Both net force and net torque = 0

Answer

Complete mechanical equilibrium requires both zero net force (translational) and zero net torque (rotational).

Question 5

An elevator travels from floor 1 to floor 10, accelerates for 2 s, travels at constant speed for 8 s, then decelerates for 2 s. During which phase is the rope tension greatest?

Accepted Answer

Acceleration phase

Answer

During upward acceleration, the rope must support the car's weight plus provide the net upward force, making tension greatest.

EIAT - Elevator Industry Aptitude Test Practice Test

EIAT - Elevator Industry Aptitude Test Practice Test

EIAT Forces, Torque, and Motion 5