Turn on thread page Beta
 You are Here: Home >< Physics

# Motion watch

1. I don't get why the initial velocity is 0 when you fire a rifle. This is from one of the past paper questions. I know the initial velocity = 0 when you drop something, and when you throw something up initial velocity ≠ 0. But I don't understand the case when you fire something horizontally.
2. The initial velocity is not zero - the initial VERTICAL velocity is zero if you fire horizontally.

Put it another way, a horizontal velocity has zero vertical component.
3. (Original post by phys981)
The initial velocity is not zero - the initial VERTICAL velocity is zero if you fire horizontally.

Put it another way, a horizontal velocity has zero vertical component.
Right, I sort of get it now. But how about final vertical velocity?
4. You have to calculate that using equations of motion.

You do it exactly as though the object had been dropped - in other words the fact that it is moving horizontally has NO effect on the vertical velocity.

Reply
Submit reply
Turn on thread page Beta

### 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: February 28, 2018
Today on TSR

### He lied about his age

Thought he was 19... really he's 14

### University open days

1. University of Bradford
University-wide Postgraduate
Wed, 25 Jul '18
2. University of Buckingham
Psychology Taster Tutorial Undergraduate
Wed, 25 Jul '18
3. Bournemouth University
Clearing Campus Visit Undergraduate
Wed, 1 Aug '18
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

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