You are Here: Home >< Physics

# Physics help watch

1) A small car has a mass of 1000kg and takes 0.05s to stop. Calculate the force on it when it stops from a speed of a) 15m/s b) 30m/a
2. (Original post by Girlsaredope)
1) A small car has a mass of 1000kg and takes 0.05s to stop. Calculate the force on it when it stops from a speed of a) 15m/s b) 30m/a
you need to use suvat to calculate the acceleration of the car and then use f=ma

note 15 and 30 m/s are quite fast and 0.05s is a short time... so the force might be surprisingly large.

3. How do you answer Q3b (both part i and ii)?

Posted from TSR Mobile
4. a) What would the total rest energy of a positron and electron be? This would be the minimum energy of any photon produced.
b) i and ii) Energy from the rest mass of the positron and electron, plus kinetic energy of electron, goes into two photons. So how much would each have?

### Related university courses

TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

This forum is supported by:
Updated: January 28, 2017
Today on TSR

### Exam Jam 2018

Join thousands of students this half term

### Solo - A Star Wars Story

Poll

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE