# A silly question

A waterfall is 100m high and the temperature of the water at the top is 12℃.Assume that all the kinetic energy of the water reaching the bootom is changed into internal energy. Find the temperature of water at the bottom of the waterfall.
I don't know how to calculate~ Help me please and expaining particularly~ Thank you!

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kurtlau said:
A waterfall is 100m high and the temperature of the water at the top is 12℃.Assume that all the kinetic energy of the water reaching the bootom is changed into internal energy. Find the temperature of water at the bottom of the waterfall.
I don't know how to calculate~ Help me please and expaining particularly~ Thank you!
At the top, the water has gravitational PE = mgh (with respect to the bottom). That PE transforms into KE as it falls. Finally, the KE is transformed into thermal energy. ΔKE = mcΔt, where c is the specific heat of water (look it up!).