Relativity Questions

If the speed of light were infinite but the postulates of special relativity still held, then

• any moving object would have infinite momentum

• time dilation would be obvious at low speeds

• length contraction would not occur

• objects could have negative kinetic energy

Assume a gram of a substance marketed as “Pure Energy” is annihilated by a gram of a second substance “Anti-Pure Energy.” How long would the energy released power a city which uses 109 watts of power?

• 40 hrs

• 25 hrs

• 50 hrs

• 65 hrs

A spaceship leaves Earth and maintains a constant force by means of a nuclear engine. As the speed of the spaceship increases, an observer on Earth finds that relative to her the magnitude of the spaceship’s acceleration is

• 0

• decreasing

• constant

• increasing

Fireworks go off at the same time according to Earth clocks in two cities, Alum and Boron, that are 300 km apart. The people in a spaceship that is flying in a straight line from Alum to Boron at 0.8c also observe the fireworks. Do they see the fireworks in the two cities simultaneously? If the people in the spaceship say the fireworks were not simultaneous in Alum and Boron, how long before or after the fireworks flashed at Alum did the fireworks flash at Boron according to their calculations? (The spaceship is directly over Alum when the fireworks flash.)

• Yes; 0

• Before; 1x10–3 s

• After; 1x10–3 s

• Before; 1.3x10–3 s

An object moving at a relativistic speed past a stationary observer appears to

• have length expanded and have a faster clock

• have length contracted and have a slower clock

• have length contracted and have a faster clock

• have length expanded and have a slower clock

A spaceship, moving away from the Earth at a speed of 0.9c, fires a light beam backward. An observer on Earth would see the light arriving at a speed of

• 1.9c

• 0.1 c

• c

• more than 0.1c but less than c

An electron has a kinetic energy that is twice its rest energy. Determine its speed.

• 0.76 c

• 0.81 c

• 0.94 c

• 0.54 c

If you were to travel at a speed close to the speed of light, you would notice which of the following?

• Your mass has increased.

• Your pulse rate has decreased.

• Your ship has contracted

• You would notice none of these effects because you are in an inertial frame.

A difference between the special and general theories of relativity is that

• special relativity deals with accelerated system

• general relativity deals with accelerated systems

• special relativity is valid only in stationary reference frames

• general relativity only deals with swiftly moving objects

The purpose of the Michelson-Morley experiment was to

• determine the velocity of light

• detect possible motion of the Earth relative to the sun

• detect possible motion of the sun relative to the ether

• detect possible motion of the Earth relative to the ether.