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    • Thread Starter

    Please can someone kindly help me with a physics question on my assignment. The question is:

    A 300kg roller coaster car starts from rest at point A and coasts down the track. If the retarding friction force is 20N along the way, how fast is the car going?

    a) At point B
    b) At point C

    Distance AB= 200m
    Distance BC= 120m
    Point A is 50m above point B and 20m above point C.

    I know i need to use work, power and energy but don't know what equation to apply to the question.
    Any help would be much appreciated. Thanks

    I don't think you need to bring power into this. Just energy

    Work Done = Force x Distance
    Change in gravitational potential = mass x 9.8 x change in height

    That's probably all you need

    (Original post by Wolly Bolly)
    what the **** is this to do with mechanics, perhaps invest in a set of useful tools insted
    I'm pretty sure using mgh counts as mechanics. I don't see the bio link, but she might just be studying biomechanics, and a physics class might have asked this question...
    • Thread Starter

    Biomechanics is the title of the unit i am studying and this question has been given to us by our teacher!!
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