FCTC Applying Mechanical Reasoning 2

Question 1

A lever is 10 feet long with the fulcrum placed 2 feet from the load end. To lift a 200-lb load, approximately how much force must be applied at the other end?

Accepted Answer

50 lb

Answer

With an 8-foot effort arm and 2-foot load arm, mechanical advantage is 4, so 200 ÷ 4 = 50 lb of force needed.

Question 2

Two gears mesh together. Gear A has 40 teeth and Gear B has 10 teeth. If Gear A rotates at 100 RPM, how fast does Gear B rotate?

Accepted Answer

400 RPM

Answer

Gear ratio = 40/10 = 4, so Gear B rotates 4 times faster: 100 × 4 = 400 RPM.

Question 3

A block and tackle system has 4 rope segments supporting the load. If the load weighs 400 lb, how much pulling force is required (ignoring friction)?

Accepted Answer

100 lb

Answer

With 4 supporting rope segments, the mechanical advantage is 4, so 400 ÷ 4 = 100 lb of force is needed.

Question 4

A hydraulic press has an input piston with area 2 sq in and an output piston with area 20 sq in. If 50 lb of force is applied to the input, what force does the output exert?

Accepted Answer

500 lb

Answer

Hydraulic mechanical advantage = output area ÷ input area = 20/2 = 10, so output force = 50 × 10 = 500 lb.

Question 5

A wedge is being driven into a log. What happens to the mechanical advantage if the wedge angle is made smaller (thinner wedge)?

Accepted Answer

Mechanical advantage increases

Answer

A thinner wedge has a smaller angle, which increases mechanical advantage, making it easier to split the wood with less force.

FCTC Test Practice Test

FCTC Test Practice Test

FCTC Applying Mechanical Reasoning 2