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

Answered by Kerr M. Physics tutor

3437 Views

See similar Physics A Level tutors

Related Physics A Level answers

All answers ▸

A ball is dropped from a 5.0m high window. Assuming air resistance is negligible, calculate the time taken for it to hit the ground.


2 Capacitors (c1 = 500mf) and (c2=300mf), are connected in parallel to a 10v d.c supply. Calculate the total capacitance of the circuit, and hence the total energy stored in the capacitors.


Two trains are heading in opposite directions on the same track. Train X has a mass of 16000kg and a speed of 2.8m/s. Train Y has a mass of 12000kg and a speed of 3.1m/s. At what speed do the joined trains move off together immediately after the collison?


What is the most effective use of the equation sheet?


We're here to help

contact us iconContact usWhatsapp logoMessage us on Whatsapptelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo

© MyTutorWeb Ltd 2013–2025

Terms & Conditions|Privacy Policy
Cookie Preferences