602 views

### A stationary observer Bob, observes Alice take 5 seconds to travel from point A to B at 0.95c. How much time does Alice measure the journey from A to B to take?

This question is all about the application of Special Relativity.

In order to solve this problem we need to identify that the correct equation to use here is:

t= (gamma factor)t0

Where t is the time observed by Bob, t0 is the time observed by Alice and the gamma factor = 1/Sqrt(1-(v2/c2)

We need to rearrange the equation for t0, giving

t0=t/(gamma factor)

t0= t(Sqrt(1-(v2/c2))

Subsituting t =5 s, v = 0.95c, we obtain:

t0=(5 s)(Sqrt(1-0.952))

t0 = 1.56 s

2 years ago

Answered by Elizabeth , an A Level Physics tutor with MyTutor

## Still stuck? Get one-to-one help from a personally interviewed subject specialist

#### 148 SUBJECT SPECIALISTS

£20 /hr

Degree: Physics (Bachelors) - Kings, London University

Subjects offered:Physics, Maths+ 1 more

Physics
Maths
Further Mathematics

“Positive, Dedicated, Motivating, Calm, Patient, Understanding, Professional, Organised, Experienced, Focused, Enthusiastic, Passionate”

MyTutor guarantee

|  1 completed tutorial

£20 /hr

Degree: Physics (Bachelors) - Imperial College London University

Subjects offered:Physics, Maths+ 3 more

Physics
Maths
Further Mathematics
Chemistry
-Personal Statements-

“Undergraduate Physicist with lots of experience in teaching in different fields and age groups, looking to instil a passion for learning into students.”

£20 /hr

Degree: Aeronautics and Astronautics (Integrated Masters) - Southampton University

Subjects offered:Physics, Maths+ 3 more

Physics
Maths
Extended Project Qualification
Chemistry
-Personal Statements-

“Aero and Astro Engineering student specialising in Maths and Physics A-level and GCSE.”

MyTutor guarantee

|  1 completed tutorial

£30 /hr

Degree: Computer science and Physics (Bachelors) - Durham University

Subjects offered:Physics, Maths+ 2 more

Physics
Maths
German
Computing

“Hi! I'm Lizzy and I am currently reading Maths, Physics and Computer Science at Durham University. Drop me a line for anything STEM related!”

### You may also like...

#### Other A Level Physics questions

A roller coaster has a loop, r = 20m, how fast should it travel so that riders don't fall out?

A pendulum of mass m is released from height h with a speed v at the bottom of its swing. a) What is the gravitational potential energy at height h and the kinetic energy at the bottom of its swing? b) Use conservation of energy to define the speed v.

Why are electron volts used instead of Joules in Quantum Phenomena and how do you convert between the two?

What is the difference between a scalar and a vector? Give 3 examples of each.

We use cookies to improve your site experience. By continuing to use this website, we'll assume that you're OK with this.