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exam help******easy physics question

  • 23-08-2012 7:42pm
    #1
    tyw3724e
    Registered Users, Registered Users 2 Posts: 20 ✭


    A 0.2kg stone is thrown vertically downwards with a speed of 12.0m/s from the edge of a cliff 35.om high.

    1 what is thw speed of the stone just before hitting the bottom of the cliff.

    2 what is its kinetic energy when the stone is released,

    3 what is its potential energy when the stone is released, take the potential energy at the bottom of the cliff as 0

    4 calculate the speed of the stone just before hitting the bottom of the cliff using the conservation of energy


Comments

  • #2
    Delphi91
    Registered Users, Registered Users 2 Posts: 1,501 ✭✭✭Delphi91


    I won't do the question for you but I'll give you some pointers....:D

    Have a look at the information that you are given and write down all the quantities and the symbols that are used to represent them, eg m = mass, s = distance (height of cliff), etc. There is one variable not explicitly stated as a number, but a little thought will help identify it.

    When you've done that, have a look at the equations of motion, the formulas for both kinetic and potential energy and the concept of conservation of energy.

    In relation to the equations of motion, which one will give you speed given the information stated at the start of the question (bear in mind, you may not need all the information stated at the start - some of it is used for the other questions!)

    The answer to parts 1 and 4 should be the same, but in the case of 4, you get the answer a different way.


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