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    bit stuck please help me out. these got covered too quickly in lesson and cant understand my notes.

    1.) an object falls from rest through a height H to hit the ground with a speed of 25ms-1. using energy considerations and assuming there is no air resistance, find H.

    a seperate question

    2.) a stone of mass 0.8kg is dropped from a height of 1.5m into a pond. Find the kinetic energy of the stone as it hits the water. the stone then begins to sink in the water with a speed o 2.1ms-1. determine the kinetic energy lost when the stone strikes the water.
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    1) Just plug all the information you have into a SUVAT formula:
    V=25 U=0 A=9.8 S=?
    V²=U²+2AS

    2) To start with do the same as the first question:
    V=? U=0 A=9.8 S=1.5
    V²=U²+2AS
    And when you get V put it into
    Kinetic Energy=1/2MV²
    M=0.8 V=?

    To find the kinetic energy lost put 2.1 into the equation as V and subtract the answer you get from your original answer for the stone's kinetic energy
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    thats really helpful i agree with it all.

    however in no.1 is there another way as it says using energy considerations?
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    1/2mv^2=mgh
    1/2v^2=gh
 
 
 
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