You are Here: Home >< Maths

# Mechanics question watch

1. Two particles A and B of mass 4kg and 3kg respectively are connected by a light in extensible string which passes over a smooth fixed pulley. The particles are released from rest with the string taut.

a) Find the tension in the string

b) When A has traveled a distance of 2m it strikes the ground and immediately comes to rest

Assuming that B does not hit the pulley find the greatest height that B reaches above its initial position.

So i found the tension to part a which is 33.6N

This is what i did for part b):

I found the a=1.4ms^2

For A: u=0 s=2 a=1.4 v=?
V^2=u^2 +2as
I got 2.4m/s 2sf

For B:
u=2.4 a=1.4 v=0 s=?
V^2=u^2 +2as
I got 2.1m

Can anyone help me identify where i faulted please.
2. (Original post by Tynos)

For B:
u=2.4 a=1.4 v=0 s=?
V^2=u^2 +2as
I got 2.1m

Can anyone help me identify where i faulted please.
That was a when there was tension pulling the particle upwards

That tension has gone so a has changed
3. (Original post by TenOfThem)
That was a when there was tension pulling the particle upwards

That tension has gone so a has changed
How could i find the changed acceleration?
4. (Original post by Tynos)
How could i find the changed acceleration?
You know what the acceleration is

If you drop a ball what is the acceleration
5. (Original post by TenOfThem)
You know what the acceleration is

If you drop a ball what is the acceleration

Ahh.. thank you.
6. (Original post by TenOfThem)
You know what the acceleration is

If you drop a ball what is the acceleration
I used 9.8ms^-2 but cannot seem to get 16/7, i get 0.3ms^-2
7. (Original post by Tynos)
I used 9.8ms^-2 but cannot seem to get 16/7, i get 0.3ms^-2
That is motion for part (b)

8. (Original post by TenOfThem)
That is motion for part (b)

Im confused.
9. (Original post by Tynos)
Im confused.
You're interested in the greatest height above its initial position.

This will equal the distance it moved when there was tension in the string, plus the distance it moved up when moving freely under gravity.

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: April 15, 2013
Today on TSR

### Tuition fees under review

Would you pay less for a humanities degree?

### Can I get A*s if I start studying now?

Discussions on TSR

• Latest
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

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