Test Index

JAMB Physics 2019 Paper

© africaexams.com

Question : 100

Total: 100

A mass of 0.5kg is whirled in a vertical circle of radius 2m at a steady rate of 2 rev/s. Calculate the centripetal force

164N
160N
158N
172N

Solution:

Concept:

Centripetal force is given by

F = m r \omega^2

, where

\omega = 2\pi f

.

Explanation:

The mass is

m = 0.5\ \mathrm{kg}

and the radius is

r = 2\ \mathrm{m}

.

The steady rate is

f = 2\ \mathrm{rev/s}

, so the angular velocity is:

\omega = 2\pi f = 2\pi \times 2 = 4\pi\ \mathrm{rad/s}

Now substitute into the centripetal force formula:

F = m r \omega^2 = 0.5 \times 2 \times (4\pi)^2

F = 1 \times 16\pi^2 \approx 157.75\ \mathrm{N}

This is approximately

158\ \mathrm{N}

.

Answer:

C. 158N

© africaexams.com

Go to Question:

Prev Question