a copper ball is dropped from a vertical height of 1200 m.If initial temp. of copper ball at the height is 12 degree celcius, what is its temp. on reaching the ground? Assume all its kinetic energy changes to heat energy and sp. heat capacity of copper is 400 J/kg/c and g = 10 m/s2 ?

Asked by nisha_vini29 | 20th Jun, 2016, 03:58: PM

Expert Answer:

begin mathsize 12px style Hi space Nisha comma
As space the space ball space is space dropped space from space straight a space height space straight h comma space the space potential space energy space gets space converted space into space kinetic space energy.
Now comma space it space is space given space that space the space entire space kinetic space energy space goes space in space changing space the space temperature space of space the space copper space ball.
So comma space we space have
mgh equals mcΔT
therefore increment straight T equals open parentheses straight T subscript straight f minus straight T subscript straight i close parentheses equals gh over straight c equals fraction numerator 10 cross times 1200 over denominator 400 end fraction equals 30
Therefore comma space the space temperature space when space it space touches space the space ground space is
straight T subscript straight f equals 30 plus 12 equals 42 space degree straight C end style

Answered by  | 20th Jun, 2016, 06:23: PM

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