SIFT Physics and Simple Machines Questions and Answers

Question 1

An aircraft is in straight and level flight at a constant velocity. Which of the following statements about the four fundamental forces acting on it is true?

Accepted Answer

Thrust equals drag, and lift equals weight.

Answer

Thrust is greater than drag.

Answer

Lift is greater than weight.

Answer

Lift equals drag, and thrust equals weight.

Question 2

A winch uses a handle with a rotational radius of 15 inches to turn an axle with a radius of 3 inches. What is the ideal mechanical advantage (IMA) of this wheel and axle system?

Accepted Answer

5

Answer

45

Answer

12

Answer

0.2

Question 3

A crane lifts a 500-pound engine 8 feet into the air. If the lift takes 4 seconds to complete, what is the power expended by the crane, ignoring friction?

Accepted Answer

1000 ft-lbs/sec

Answer

4000 ft-lbs/sec

Answer

125 ft-lbs/sec

Answer

16,000 ft-lbs/sec

Question 4

In a third-class lever, which of the following is located between the other two components?

Accepted Answer

The effort (force)

Answer

The fulcrum

Answer

The load (resistance)

Answer

The mechanical advantage

Question 5

Using a block and tackle pulley system with an ideal mechanical advantage (IMA) of 4, how much rope must a user pull to lift a heavy object a vertical distance of 3 feet?

Accepted Answer

12 feet

Answer

0.75 feet

Answer

3 feet

Answer

7 feet

Question 6

A screw is a simple machine that is functionally a modification of which other simple machine?

Accepted Answer

An inclined plane

Answer

A wheel and axle

Answer

A lever

Answer

A pulley