Question

The angle between velocity and acceleration of a particle describing uniform circular motion is

• A. $45 ^{\circ}$
• B. $60^{\circ}$
• C. $90^{\circ}$
• D. $180^{\circ}$

Answer 1

The Correct Option is C

When an object follows a circular path at a constant speed, the motion of object is called uniform circular motion
Although the speed does not vary the particle is accelerating because the velocity changes its direction at every point on circular track.

The acceleration is centripetal, which is perpendicular to motion at every point and acts along the radius and directed towards the centre of the curved circular path.
$=\frac{90 \times 10^{-3}}{\frac{22}{7} \times\left(\frac{0.1 \times 10^{-3}}{2}\right)^{2}} $
$=\frac{90 \times 10^{-3}}{3.14 \times\left(\frac{0.1 \times 10^{-3}}{2}\right)^{2}} $
$= 12000 \times 10^{3}$
$= 12 \times 10^{7} \,A / m ^{2}$