You are Here: Home >< Maths

# Impulse formula question Watch

1. Ok, I've learned the formula for Impulse to be Impulse = M(V-U), but then there's also a bit = FT and I know that it stands for Force x Time. However, I'm a bit unsure of when to use it. Sometimes I think there have been questions where I just use the M(V-U) bit and now I'm looking at the mark scheme for a question where they have used the FT bit as well. So how do you know when to use it? Is it *always* used or just in some instances?
2. (Original post by SMC879)
Ok, I've learned the formula for Impulse to be Impulse = M(V-U), but then there's also a bit = FT and I know that it stands for Force x Time. However, I'm a bit unsure of when to use it. Sometimes I think there have been questions where I just use the M(V-U) bit and now I'm looking at the mark scheme for a question where they have used the FT bit as well. So how do you know when to use it? Is it *always* used or just in some instances?
Depends on the info you're given - often you know what the change in momentum of a particle or object is, but you don't know the time interval over which a force acts; or it may be an instantaneous change in momentum in which case you need the mv-mu version.

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: May 12, 2013
Today on TSR

### Am I pregnant?

...or just paranoid?

### A robot wrote Harry Potter?

Discussions on TSR

• Latest
• ## See more of what you like on The Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

• Poll
Useful resources

### Maths Forum posting guidelines

Not sure where to post? Read the updated guidelines here

### How to use LaTex

Writing equations the easy way

### Study habits of A* students

Top tips from students who have already aced their exams

## Groups associated with this forum:

View associated groups
Discussions on TSR

• Latest
• ## See more of what you like on The Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

• 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

Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.