NSAA NSAA Physics - Mechanics 2

Question 1

A projectile is launched horizontally at 15 m/s from a height of 20 m. How long does it take to hit the ground (g = 10 m/s²)?

Accepted Answer

2 s

Answer

Using h = ½gt²: 20 = ½×10×t², giving t² = 4, so t = 2 s.

Question 2

What is the momentum of a 0.5 kg ball moving at 12 m/s?

Accepted Answer

6 kg·m/s

Answer

Momentum p = mv = 0.5 × 12 = 6 kg·m/s.

Question 3

A force of 50 N acts on an object over a displacement of 8 m in the direction of the force. What work is done?

Accepted Answer

400 J

Answer

Work = Force × displacement = 50 × 8 = 400 J.

Question 4

A pulley system has a mechanical advantage of 4. What input force is needed to lift a 200 N load?

Accepted Answer

50 N

Answer

Input force = Load / MA = 200 / 4 = 50 N.

Question 5

An object of weight 60 N is held stationary on a surface. What is the normal reaction force from the surface?

Accepted Answer

60 N

Answer

By Newton's third law, the normal force equals the weight when the object is in equilibrium on a horizontal surface.

NSAA - Natural Sciences Admissions Assessment Practice Test