The work done by a particle moving with a velocity of 0.7 c (where c is the velocity of light) in empty space free of electromagnetic field and far away from all matter is:

Question

The work done by a particle moving with a velocity of 0.7 c (where c is the velocity of light) in empty space free of electromagnetic field and far away from all matter is: (A) positive (B) negative (C) zero (D) infinite

Tardigrade Admin · Accepted Answer

Acceleration of the particle a=(dv/dt)=(d/dt)(0.7c)=0 ( ∵ c= constant) Force on the particle F=ma=0 Thus, work done by a particle will be zero.

Q. The work done by a particle moving with a velocity of $0.7 c$ (where c is the velocity of light) in empty space free of electromagnetic field and far away from all matter is:

positive

negative

zero

infinite

Acceleration of the particle
$a = \frac{d v}{d t} = \frac{d}{d t} (0.7 c) = 0$
( $∵$ $c =$ constant)
Force on the particle
$F = ma = 0$
Thus, work done by a particle will be zero.

Q. The work done by a particle moving with a velocity of 0.7c (where c is the velocity of light) in empty space free of electromagnetic field and far away from all matter is: