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Question
A block of mass 100 g slides on a rough horizontal surface. If the speed of the block decreases from 10 m s−1 to 5 m s−1, find the thermal energy developed in the process.
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Solution
Given:-
Mass of the block = 100 g = 0.1 kg
Initial speed of the block = 10 m/s
Final speed of the block = 5 m/s
`"Initial kinetic energy of the block"=1/2xx0.1xx10^2=5J`
`"Final kinetic energy of the block"=1/2xx0.1xx5^2=1.25J`
Change in kinetic energy of the block = 5 - 1.25 = 3.75 J
Thermal energy developed is equal to the change in kinetic energy of the block. Thus,
Thermal energy developed in the process = 3.75 J
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