## 28.1 Einstein’s Postulates

Which of the following statements describes the Michelson-Morley experiment?

- The speed of light is independent of the motion of the source relative to the observer.
- The speed of light is different in different frames of reference.
- The speed of light changes with changes in the observer.
- The speed of light is dependent on the motion of the source.

## 28.4 Relativistic Addition of Velocities

What happens when velocities comparable to the speed of light are involved in an observation?

- Newton’s second law of motion, $F=ma$ , governs the motion of the object.
- Newton’s second law of motion, $F=ma$ , no longer governs the dynamics of the object.
- Such velocities cannot be determined mathematically.
- None of the above

## 28.6 Relativistic Energy

A mass of 50 g is completely converted into energy. What is the energy that will be obtained when such a conversion takes place?

The relativistic energy of a particle in terms of momentum is given by:

- $E=\sqrt{{p}^{2}{c}^{2}+{m}_{0}^{2}{c}^{4}}$
- $E=\sqrt{{p}^{2}{c}^{2}+{m}_{0}^{4}{c}^{4}}$
- $E=\sqrt{{p}^{2}{c}^{2}+{m}_{0}^{2}{c}^{2}}$
- $E=\sqrt{{p}^{2}{c}^{4}+{m}_{0}^{2}{c}^{2}}$