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Help pulleys question a- level m1

2 particles A and B have masses 2m and 3m respectively. The particles are attached to the ends of a light inextensible string. Particle A is held at rest on a smooth horizontal table. Particle B hangs at rest vertically below the pulley with the string taut. Particle A is released from rest. Assuming that A has not reached the pulley, find
a) the acceleration of B
b)the tension in the string
c) the magnitude and direction of the force exerted on the pulley by the string

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Reply 1

DylanJ42

Original post by thefatone

Here is a diagram (practice drawing these)

For a) create simult equations and solve

b) use the equations with the info you found from a)

c) harder to explain, look at the top right of the diagram, you know T so make a right angled triangle and find "F"

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(edited 8 years ago)

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Reply 2

thefatone

Original post by DylanJ42

Here is a diagram (practice drawing these)

For a) create simult equations and solve

b) use the equations with the info your found from a)

c) harder to explain, look at the top right of the diagram, you know T so make a right angled triangle and find "F"

Posted from TSR Mobile

so tension is the same with arrows going away and towards the pulley?

Reply 3

DylanJ42

Original post by thefatone

so tension is the same with arrows going away and towards the pulley?

yes

there's only one string so tension is the same at both points

Reply 4

DylanJ42

Original post by thefatone

so tension is the same with arrows going away and towards the pulley?

btw in future post questions and the maths forum here; http://www.thestudentroom.co.uk/forumdisplay.php?f=38

There's more chance of it being seen that way :biggrin:

best of luck with maths this year and tag me if you need anymore help (and hopefully I can help) :h:

Reply 5

thefatone

Original post by DylanJ42

yes

there's only one string so tension is the same at both points

so can i assume the angle will be 45 degrees since F will cut the right angle directly in half? if so then after that can i use a^2+b^2=c^2?

Reply 6

thefatone

Original post by DylanJ42

btw in future post questions and the maths forum here; http://www.thestudentroom.co.uk/forumdisplay.php?f=38

There's more chance of it being seen that way :biggrin:

best of luck with maths this year and tag me if you need anymore help (and hopefully I can help) :h:

ah ok

Reply 7

DylanJ42

Original post by thefatone

so can i assume the angle will be 45 degrees since F will cut the right angle directly in half? if so then after that can i use a^2+b^2=c^2?

perfect

the questions on inclined planes wont be 45^othough, are you edexcel M1?

Reply 8

thefatone

Original post by DylanJ42

perfect

the questions on inclined planes wont be 45^othough, are you edexcel M1?

yes however if you do the question and resolve etc i have managed to get a tension of 12mg/5, not sure if that's right or wrong :/

Reply 9

thefatone

Original post by DylanJ42

i got 12root2mg/5 as the size of the force can you possibly check if it's right?

Reply 10

DylanJ42

Original post by thefatone

yes however if you do the question and resolve etc i have managed to get a tension of 12mg/5, not sure if that's right or wrong :/

Sorry i a had to go fordinner

i got 6mg/5 for the tension, post your workings if possible?

Also Exercise 3F question 9 part c, have a look at it

Reply 11

DylanJ42

Original post by thefatone

i got 12root2mg/5 as the size of the force can you possibly check if it's right?

my answer was half of that, but only because we got different tensions, your method is correct (and maybe your answer is correct too, I could have made a mistake)

I will post my workings (considering you have done the question and you can compare if you like)