Question

Look at the figure above. If an alien flew by at v = 0.94 c, how long would one hour of Earth take on his clock?

1.20 minutes

2.one hour

3.30 minutes

4.90 minutes

5.180 minutes

Look at the figure above. If Helga's spaceship is 100m long and 10m tall at rest, and she flew by v = 0.90 c, how long and tall would her spaceship be?

1.100 m long and 4.3 m tall

2.100 m long and 23 m tall

3.43 m long and 10 m tall

4.230 m long and 10 m tall

Answer 1

lorentz Factor y = 1/(sqrt(1 - v^2/c^2)

y = 1/sqrt(1 - 0.94^2)

y = 2.93

time period T = To/y

T = 1/2.93

T = 0.341* 60

T = 20 minutes , option A

-----------------------------------

y = (1/sqrt(1 - v^2/c^2)

y = 1/sqrt(1 - 0.9^2)

y = 2.29

Length = 100m

tall = 10 * 2.29 - 22.9 m or 23 m

option 2 is the ANSWER