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    Which part? What have you tried?
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    Which part? What have you tried?

    It will be useful if you post all your working and show us the diagram that you have drawn.

    EDIT: RDKGames snap!
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    I have done part a and got acceleration to be 4.48ms^-2
    Need help on part b
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    The string breaks so there's no tension anymore.

    Now, consider the work done by the friction and the loss of mechanical energy
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    (Original post by shahs341)
    I have done part a and got acceleration to be 4.48ms^-2
    Need help on part b
    It's very important that you tell us what you have tried and why you are stuck. This is a topic that is taught differently by different teachers so we need to know how you normally go about a question like this. If you post your working then that will show us.
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    My working out:

    The diagram I used: Name:  IMG_0196.jpg
Views: 28
Size:  471.3 KB


    Part a working out: https://www.thestudentroom.co.uk/att...1&d=1483978356

    attempt at b working out: https://www.thestudentroom.co.uk/att...1&d=1483978400
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    (Original post by shahs341)
    My working out:

    The diagram I used:
    I haven't checked all your working but I think you've made a mistake when considering the gravitational potential energy.

    Remember that the gain in GPE is equal to mgh where h is the vertical distance moved. But you need to work out the distance moved up the slope.

    Does that help?
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    (Original post by shahs341)
    My working out:

    The diagram I used: Name:  IMG_0196.jpg
Views: 28
Size:  471.3 KB


    Part a working out: https://www.thestudentroom.co.uk/att...1&d=1483978356

    attempt at b working out: https://www.thestudentroom.co.uk/att...1&d=1483978400
    You need to also consider the work done by friction
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    When B descend down by 1m, does A also move 1m up the slope?
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    (Original post by metrize)
    You need to also consider the work done by friction
    K.E lost = mgh gained - work done by the frictional force ?
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    (Original post by notnek)
    I haven't checked all your working but I think you've made a mistake when considering the gravitational potential energy.

    Remember that the gain in GPE is equal to mgh where h is the vertical distance moved. But you need to work out the distance moved up the slope.

    Does that help?
    no sorry tried this and didn't get the right answer
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    (Original post by shahs341)
    When B descend down by 1m, does A also move 1m up the slope?

    yeah thats right
    (Original post by shahs341)
    K.E lost = mgh gained - work done by the frictional force ?
    I got taught loss GPE + loss KE = work done by friction



    I can try to answer it if you give me 5 mins, do you have the answer with you?
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    (Original post by shahs341)
    When B descend down by 1m, does A also move 1m up the slope?
    Yes but is that 'h' in the formula mgh?
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    (Original post by metrize)
    yeah thats right


    I got taught loss GPE + loss KE = work done by friction



    I can try to answer it if you give me 5 mins, do you have the answer with you?
    the answer from the book is 1.51 m

    good luck!
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    (Original post by Muttley79)
    Yes but is that 'h' in the formula mgh?
    yes that's h - the vertical distance moved
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    (Original post by shahs341)
    yes that's h - the vertical distance moved
    1 metre up the slope is not 1 metre vertically ...
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    Here's what I did, see if you can follow it and get the answer:

    Starting from Loss KE + Loss GPE = Work done by friction

    I let d be the distance it moves up the slope. Since I let d be the distance up the slope, my loss in GPE will be negative
    Work done by friction is d mu R.

    Remember that the vertical height the object moves if it goes d up the slope is dsin theta vertically
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    (Original post by metrize)
    Here's what I did, see if you can follow it and get the answer:

    Starting from Loss KE + Loss GPE = Work done by friction

    I let d be the distance it moves up the slope. Since I let d be the distance up the slope, my loss in GPE will be negative
    Work done by friction is d mu R.

    Remember that the vertical height the object moves if it goes d up the slope is dsin theta vertically
    Well explained, I got the answer thanks!
 
 
 
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