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**barbie19022002****Member**- Registered: 2013-05-24
- Posts: 1,314

I didn't expect in such a early period of time we will have ch-**force and the laws of motion** and now I am stuck with it..pls..some one help me..:)

Two Objects of Masses 100g and 200g are moving along the same line and direction with the velocity of 2 m s-1 and 1 m s-1 respectively. They collide and after collision, the first object moved at the velocity of 1.67 m s-1. Determine the velocity of the second object.

*Last edited by barbie19022002 (2013-07-22 19:51:36)*

Jake is Alice's father, Jake is the ________ of Alice's father?

Why is T called island letter?

think, think, think and don't get up with a solution...

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**bob bundy****Moderator**- Registered: 2010-06-20
- Posts: 7,501

hi barbie19022002

You need to use the equation for conservation of momentum:

let m1 = 100 and m2 = 200

u1 = 2 and u2 = 1

After the collision the masses are the same but the velocities are now v1 (= 1.67 ) and v2

So you can 'plug in' the numbers and work out v2

Bob

Children are not defined by school ...........The Fonz

You cannot teach a man anything; you can only help him find it within himself..........Galileo Galilei

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**barbie19022002****Member**- Registered: 2013-05-24
- Posts: 1,314

can you explain it to me more nicely...pls

Jake is Alice's father, Jake is the ________ of Alice's father?

Why is T called island letter?

think, think, think and don't get up with a solution...

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Are you aware of the law of conservation of momentum?

'And fun? If maths is fun, then getting a tooth extraction is fun. A viral infection is fun. Rabies shots are fun.'

'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'

I'm not crazy, my mother had me tested.

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**barbie19022002****Member**- Registered: 2013-05-24
- Posts: 1,314

Ya..I am...but I don't know I to use it..:P

Jake is Alice's father, Jake is the ________ of Alice's father?

Why is T called island letter?

think, think, think and don't get up with a solution...

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**bob bundy****Moderator**- Registered: 2010-06-20
- Posts: 7,501

hi barbie19022002

If you get hit by a truck it hurts a lot more than if you get hit by a fly. Clearly the mass of a moving object makes a difference.

But the velocity does too. A fly that hits you at 60 mph hurts a lot more than a fly that just gently lands on you.

The momentum of a moving object is a measure of these two:

**momentum = mass x velocity**

When two objects collide they may swap some momentum. This happens all the time in a game of snooker or pool.

The total momentum before and after the collision is constant. This can enable you to work out how fast an object is moving after the event.

For your example:

so v2 is given by

Can you finish this now?

Bob

Children are not defined by school ...........The Fonz

You cannot teach a man anything; you can only help him find it within himself..........Galileo Galilei

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**barbie19022002****Member**- Registered: 2013-05-24
- Posts: 1,314

let me try once in my rough..

And thanks to make me understand more clearly...because in this chapter I was hardly able to understand anything clearly...:P

Thanks, Bob Bundy....

*Last edited by barbie19022002 (2013-07-22 19:55:36)*

Why is T called island letter?

think, think, think and don't get up with a solution...

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**bob bundy****Moderator**- Registered: 2010-06-20
- Posts: 7,501

This page has some great videos on this. I recommend you view the Richard Garriott space video first. (4th one on page)

http://physicsnet.co.uk/a-level-physics … -concepts/

Bob

Children are not defined by school ...........The Fonz

You cannot teach a man anything; you can only help him find it within himself..........Galileo Galilei

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