Question

A particle is acted upon by a force of constant magnitude which is
always perpendicular to the velocity of the particle. It follows that
(A) KE of particle changes with time
(B) acceleration of particle is constant
(C)
velocity of particle is constant
(D) kE of particle is constant​

Answer 1

Explanation:

When a force of constant magnitude which is always perpendicular to the velocity of the particle acts on a particle, the work done and hence change in kinetic energy is zero.

Since the particle is acted upon by a force of constant magnitude which is always perpendicular to the velocity of the particle, so work done by the force in the direction of the velocity is zero. So the magnitude of velocity will not change due to the force.

Kinetic energy is KE=

2

1

mv

2

=constant.

Now mass and magnitude of velocity will always be constant in this given situation so the kinetic energy will also be constant.