Test Index

JAMB Physics 2019 Paper

Question : 68

Total: 100

Solution:

Concept:

Uniform velocity means zero acceleration, so the applied force equals the frictional force.

Explanation:

The box has mass

m = 500 \, \text{kg}

Taking

g = 10 \, \text{m/s}^2

, the weight is

W = mg = 500 \times 10 = 5000 \, \text{N}

Since the floor is horizontal, the normal reaction

R

equals the weight:

R = 5000 \, \text{N}

The applied force is

F = 2000 \, \text{N}

, and at uniform velocity, friction

f = F = 2000 \, \text{N}

The coefficient of friction is

\mu = \frac{f}{R} = \frac{2000}{5000} = 0.4

Answer:

\mu = 0.4

Correct option: D. 0.4.

Go to Question:

Prev Question

Next Question