OAR OAR Mechanical Reasoning 2

Question 1

A lever is 10 feet long with the fulcrum 2 feet from the load end. If a 400 lb load is placed on the short end, how much force is needed on the long end to balance it?

Accepted Answer

100 lb

Answer

Using the lever principle: 400 × 2 = F × 8, so F = 100 lb.

Question 2

Water flows through a pipe that narrows from 4 inches in diameter to 2 inches. Compared to the wide section, the water speed in the narrow section is:

Accepted Answer

Four times as fast

Answer

Flow rate is constant; halving the diameter quarters the area, so speed quadruples.

Question 3

A block sits on a ramp inclined at 30°. The component of gravity acting parallel to the ramp surface (pulling the block down the slope) equals:

Accepted Answer

mg × sin30°

Answer

The component of gravity along an incline is mg × sinθ.

Question 4

Two gears mesh together. Gear A has 12 teeth and Gear B has 36 teeth. If Gear A turns at 180 RPM, what is the speed of Gear B?

Accepted Answer

60 RPM

Answer

Gear ratio = 12/36 = 1/3, so Gear B turns at 180 × (1/3) = 60 RPM.

Question 5

A spring with a spring constant of 50 N/m is compressed 0.4 m from its natural length. How much potential energy is stored in the spring?

Accepted Answer

4 J

Answer

Elastic potential energy = ½kx² = ½ × 50 × 0.16 = 4 J.

OAR Test Practice Test

OAR Test Practice Test

OAR OAR Mechanical Reasoning 2