Calculate the length of a 120m (as measured by the astronaut) spaceship travelling at 0.85c as measured by a stationary observer

The length of the spaceship of 120m was measured at rest relative to the spaceship so we will take that as the proper length, dennoted Lproper
We first calculate the Lorentz factor:
Ɣ = 1/sqrt(1-(v/c)2)
Ɣ = 1/sqrt(1-0.852)
Ɣ = 1.8986... (Keep this number in your calculator as rounding now will affect your final answer)
Now, relate this to the formula for length contraction:
L = Lproper / Ɣ
L = 120/1.8986...
L = 63.2m as measured by the stationary observer

KM

Related Physics A Level answers

All answers ▸

An object orbits Earth at an altitude of 200 kilometers above the planet’s surface. What is its speed and orbital period?


State assumptions made about the motion of the molecules in a gas in the derivation of the kinetic theory of gases equation.


A car is travelling at 20 m/s. The accelerator is applied, causing an acceleration of 2m/s^s. How fast is the car travelling after 10 seconds of acceleration?


Describe one technique you could use to measure the threshold voltage for LEDs.