Q. The rocket's speed was measured to be 1.49c. The rocket's rest length is 380 m. An observer flying by measured the rocket to be 199 m long. A rocket flying towards the Sun at 0.97c measured the speed of the photons (particles of light) emitted by the Sun to be c. An inertial reference frame had an acceleration of 13 m/s2. The proper time interval between two events was measured to be 293 s. The time interval between the same two events (as measured by an observer not in the proper frame) was 312 s.

Q. A 20.0 g bullet strikes a 0.600 kg block attached to a fixed horizontal spring whose spring stiffness constant is 7.30 103 N/m and sets it into vibration with an amplitude of 21.5 cm. What was the speed of the bullet before impact if the bullet and block move together after impact?