1) Explain any one situation in which light behaves like a particle and one situation in which light behaves like a wave.

2) A train is moving with a speed of 50 miles per hour. A man standing in the rear of a train car throws a ball toward the front of the train with a speed of 10 miles per hour. If a stationary observer outside the train sees this happen, what speed is the ball moving with? Explain your answer.

3) Explain length and time dilation and give an example of when each is observed.

4) Explain the concept of frames of reference.