Mechanics help

a particle of mass 3 kg is attached to one end of each of two strings s1 and s2. A particle of mass 2.5kg is attached to the other end of s1, and a particle of mass 1kg is attatched to the other end of s2. The particles are held in positions shown with the strings taut and s1 passing over a smooth fixed peg. The system is released from rest. Find the acceleration of the particles and the tensions in s1 and s2

sorry but idk how to draw a pic to show you but basically its a pulley with another string under the object on the right.
so you have the 2.5kg weight on the left end of the pulley then the 3kg weight on the right end (attatched by the string, s1) of the pulley with a 1kg weight under the 3kg weight attatched together with a different string, s2.

Thanks

(edited 11 years ago)

Reply 1

TenOfThem

Are the springs or strings?

Reply 2

SDavis123

Original post by TenOfThem

Are the springs or strings?

strings

Reply 3

SDavis123

if you have the mechanics book by douglas quadling its pg 118 question 6

Reply 4

TenOfThem

Original post by SDavis123

strings

Do you want to correct your OP then, to make it easier for anyone else reading

This?

Set up an equation in T₁ and a for the 2.5 mass

Set up an equation in T₁, T₂, and a for the 3 mass

Set up an equation in T₂ and a for the 1 mass

you have 3 equations in 3 unknowns, solve them simultaneously

Reply 7

SDavis123

Original post by TenOfThem

This?

yes thanks

Reply 8

SDavis123

Original post by TenOfThem

These are the equations I get in order I think I'm going wrong with the bit to do with the bottom string

1. T-2.5g=2.5a
2. 3g +s -t =3a
3. G-s=a

Where s is the pull from the bottom string and t is the tension from upper string

This was posted from The Student Room's iPhone/iPad App

Reply 9

ghostwalker

Original post by SDavis123

Aside from the fact you used a mix of uppercase/lowercase (best to be consistent), they're fine.

Reply 10

SDavis123

Yh sorry about that autocorrect :/

This was posted from The Student Room's iPhone/iPad App

Reply 11

SDavis123

I'm having trouble solving them simultaneously :/

This was posted from The Student Room's iPhone/iPad App

Reply 12

SDavis123

Don't worry got it

This was posted from The Student Room's iPhone/iPad App

Reply 13

SDavis123

got it wrong :'(
This is what I did

This was posted from The Student Room's iPhone/iPad App

ImageUploadedByStudent Room1351949549.376361.jpg126.1KB

Reply 14

TenOfThem

Original post by SDavis123

got it wrong :'(
This is what I did

This was posted from The Student Room's iPhone/iPad App

4th line of writing should say g-a not g+a

Reply 15

SDavis123

Original post by TenOfThem

4th line of writing should say g-a not g+a

ahhhhh thanks

Reply 16

Wannarex

Qn: A particle of mass 3kg 11attached to the lover end B of aThestring upperis fixed to apointend A of the stangon the ceillinga roof. A horizontal force of 201and anOpward vertical force of2.4.91 act upon the particle makingit to be in equilibrium, with theString makingan agle a with theverticle; Find the value of of andthe tension in the string.Help me please

Reply 17

mqb2766

Original post by Wannarex

Its better to start your own thread and not to bump 8 year old threads.
Also, upload a picture of the question and describe what you've tried. You must realize your posted question is almost unreadable.