OAR OAR Mechanical Comprehension: Forces 4

Question 1

A lever has its fulcrum at the center. A 40 N force is applied 2 m from the fulcrum. To balance, what force must be applied 4 m from the fulcrum on the other side?

Accepted Answer

20 N

Answer

Torque balance: 40 × 2 = F × 4 → F = 80/4 = 20 N.

Question 2

Which quantity represents the rotational effect of a force about a pivot point?

Accepted Answer

Torque

Answer

Torque (τ = F × d) measures a force's tendency to cause rotation about a pivot.

Question 3

An object moves in a circle at constant speed. The net force on the object is directed:

Accepted Answer

Inward toward the center

Answer

Centripetal force always points toward the center of the circle to maintain circular motion.

Question 4

Two workers push a crate in the same direction: one with 250 N and one with 180 N. A friction force of 130 N opposes motion. What is the net force?

Accepted Answer

300 N

Answer

Net force = (250 + 180) − 130 = 430 − 130 = 300 N in the direction of motion.

Question 5

If you double the mass of an object while keeping the net force constant, what happens to its acceleration?

Accepted Answer

Halves

Answer

From a = F/m, doubling m while holding F constant cuts acceleration in half.

OAR Test Practice Test

OAR Test Practice Test

OAR OAR Mechanical Comprehension: Forces 4