8. A car reaches 80 kilometers per hour, then
suddenly crashes into the concrete wall. Without
a seat belt, the crash test dummy slams into the
car's dashboard because
he crash test dummy's kinetic energy drops
I hear it many times

Acoal-fired plant generates 600 mw of electric power. the plant uses 4.8 x 10^6 kg of coal each day, and the heat of combustion of coal is 3.3x 10^7 j/kg. the steam that drives the turbines is at a temperature of 300° c, and the exhaust water is at 37° c. (a) what is the overall efficiency of the plant for generating electric power? (b) how much thermal energy is exhausted each day? (c) what is the change in entropy of the universe for this heat engine? (d) using the same heat reservoirs, what is the maximum possible (carnot) efficiency for a heat engine?

When an object is heated it contracts. a. true b. false

When you push downward on a book at rest on a table, you feel an upward force. does this force depend on friction? defend your answer.