Physics 2020 JAMB Past Questions - Question 9: A particles of mass 10¯² kg is fixed to the tip of a fan blade which rotates which angular velocity of 100 rad s¯¹ . If the radius of the blade is 0.2m, the centripetal force is

Correct Answer

B

Explanation

F = mrw² = 10¯² = 10² x (100) ² X 0.2 = 20N
The centripetal force acting on the particle can be calculated using the formula:

\[ F = m \cdot r \cdot \omega^2 \]

Where:
- \( m = 10^{-2} \, \text{kg} \) (mass of the particle)
- \( r = 0.2 \, \text{m} \) (radius of the blade)
- \( \omega = 100 \, \text{rad/s} \) (angular velocity)

Plugging in these values, we get:

\[ F = 10^{-2} \times 0.2 \times (100)^2 \]
\[ F = 10^{-2} \times 0.2 \times 10000 \]
\[ F = 2 \times 10000 \]
\[ F = 2000 \, \text{N} \]

So, the centripetal force acting on the particle is 2000 N.