A body of mass 5 kg falls from a height of 20 metres on the ground and it rebounds to a height of 0.2 m. If the loss in potential energy is used up by the body, then what will be the temperature rise? `("specific heat of material = 0.09 cal gm"^(–1@)"C"^(–1))`

Options

A. `0^(@)C`
B. `4^(@)C`
C. `8^(@)C`
D. None of these

Answer

D

Explanation

`W=W_(1)-W_(2)=mgh-mgh. = mg(h-h.)`
`=5xx10(20-0.2)=5xx10xx19.8`
`=5xx198=990` joule
This energy is converted into heat when the ball strikes the earth. Heat produced is
`Q=(990)/(4.2)` calorie
`DeltaT=(Q)/(mc)=(99xx100)/(42xx5000xx0.09)=(11)/(32)""^(@)C`