NAPT - Navy Advanced Programs Principles of Motion and Forces Questions and Answers

Question 1

A 1,200 kg vehicle accelerates from 10 m/s to 30 m/s over a period of 5 seconds. What is the average net force acting on the vehicle during this acceleration?

Accepted Answer

4,800 N

Answer

1,200 N

Answer

2,400 N

Answer

6,000 N

Question 2

Which of the following scenarios best illustrates Newton's First Law of Motion (the law of inertia)?

Accepted Answer

A book remains on a table until a person picks it up.

Answer

A rocket accelerates upward by expelling hot gases downward.

Answer

It takes more force to move a heavy crate than a light one.

Answer

A baseball player hits a ball, and the bat slows down slightly.

Question 3

A sailor uses a pulley system to lift a 50 kg crate of supplies 4 meters vertically from the dock to the ship's deck. How much work is done on the crate against gravity? (Assume g ≈ 10 m/s²)

Accepted Answer

2000 J

Answer

12.5 J

Answer

200 J

Answer

500 J

Question 4

A projectile is fired from a naval gun with an initial velocity. Neglecting air resistance, which of the following statements is true about its motion?

Accepted Answer

Its horizontal velocity is constant.

Answer

Its vertical acceleration changes throughout its flight.

Answer

The net force on the projectile is zero at the peak of its trajectory.

Answer

Its speed is at a maximum at the peak of its trajectory.

Question 5

Two sailors on frictionless ice skates are at rest. Sailor A (80 kg) pushes Sailor B (100 kg), causing Sailor B to move away at a speed of 2 m/s. What is the recoil speed of Sailor A?

Accepted Answer

2.5 m/s

Answer

1.6 m/s

Answer

2.0 m/s

Answer

3.2 m/s

Question 6

A constant force is applied to an object, causing it to accelerate. If the force is doubled and the object's mass is halved, what is the effect on the object's acceleration?

Accepted Answer

It is quadrupled.

Answer

It is halved.

Answer

It remains the same.

Answer

It is doubled.