length contraction and muon decay

A student is travelling at 0.7 c to a distant planet that is stationary relative to earth. They caculate the journey based on their speed and travel distance and find that the journey was 14 lightyears (8.23E18 miles). What distance is the journey from the perspective of the students friends and family back on earth.

• 19.6 Ly

• 20.5 Ly

• 30.9 Ly

• 36.5 Ly

A student traveling at 0.7c has a spaceship which is 250 meters long according to his measurement, how long would the ship have appeared to an observer back on earth.

• 178.5 m

• 153.2 m

• 139.6 m

• 85.6 m

A space alien is planning a trip to invade earth. He knows that earth is 7 light years (4.115E13 miles) away from him, when he is stationary on his planet( which is stationary with respect to earth). How long will his journey appear to him when he reaches his top speed of 0.95c?

• 2.19 ly

• 4.72 ly

• 0.89 ly

• 5.63 ly

In which direction does the contraction of length take place?

• In a random direction

• In the direction of travel

• In all directions

• In the opposite direction of travel

What is the definition of length contraction?

• The change in color of an object that is moving relative to an observer

• The decrease in width of an object that is moving relative to an observer

• The apparent decrease in length of an object that is moving relative to an observer

• The increase in length of an object that is moving relative to an observer

What happens to the length of an object as it approaches the speed of light?

• It decreases

• It remains the same

• It becomes infinite

• It increases

The proper length is the distance between two points whose positions are measured by an observer at rest with respect to the two points.

• True

• False

The muon decay experiment supports special relativity because:

• It confirms the relativity of acceleration

• It shows high-speed particles behave classically

• It contradicts Newtonian mechanics

• It confirms Galilean transformations

What type of experimental evidence does the muon experiment provide?

• Mass-energy equivalence

• only time dilation

• Lorentz transformation

• Time dilation and length contraction

As a muon is heading towards the earths surface: From the muon’s frame of reference, what explains reaching Earth's surface?

• Earth is stationary and time slows down
  

• Time speeds up

• The atmosphere is length contracted

• Nothing — it's impossible