Q. A bowling ball with a mass of 6.8 kg strikes a stationary pin that has a mass of 1.6 kg. After the collision, the pin flies forward (in the positive x direction) with a velocity of 7.3 m/s, and the ball continues forward at 3.2 m/s (in the positive x direction). What was the original velocity of the ball? How do you solve this?

Q. A certain star is 10.6 light years away. How long would it take a spacecraft traveling 0.960c to reach that star from earth, as measured by observers:
(a) on Earth
(b) on the spacecraft
(c) What is the distance traveled according to observers on the spacecraft
(d) What will the spacecraft occupants compute their speed to be from the results of (b) and (c)?