Exam 27: Relativity

A spaceship is moving away from an asteroid with a speed of 0.80c relative to the asteroid. The spaceship then fires a missile with a speed of 0.50c relative to the spaceship. What is the speed of the missile measured by astronauts on the asteroid if the missile is fired away from the asteroid?

How much energy would be required to accelerate a 77-kg professor from rest to 90% the speed of light? (c = 3.0 × 10⁸ m/s)

A pion is an unstable particle that has a mean lifetime of 2.55 × 10^-8 s. This is the time interval between its creation in a nuclear process and its extinction into decay products, as measured in a frame of reference at rest with respect to the pion. An average pion is traveling at 0.230c relative to Earth. How far does it travel in its lifetime, relative to Earth?

How many joules of energy are required to accelerate a 1.0-kg rock from rest to a speed of 0.866c? (c = 3.0 × 10⁸ m/s)

Two spaceships approach Earth from the same direction. One has a speed of 0.21c and the other a speed of 0.34c, both relative to Earth. What is the speed of one spaceship relative to the other?

The special theory of relativity predicts that there is an upper limit to the speed of an object. It therefore follows that there is also an upper limit on which of the following properties of the object? (There could be more than one correct choice.)