Question 8: Explain why it is impossible for a particle with rest mass to move faster than the speed of light.
According to special theory of relativity
When a body is moving with relativistic velocity, we deal with its relativistic mass. Therefore, mass of the body when it is moving with the velocity of light
No material object has an infinite mass; we must need an infinite amount of energy to set the object to that speed. Consequently, we say that nobody can attain the speed of light. Therefore, speed of a particle can never be equal to the speed of light.