A girl and her bicycle have a total mass of 40 kg. At the top of the hill her speed is 5.0 m/s. The hill is 10 m high and 100 m long. If the force of friction as she rides down the hill is 24 N, what is her speed at the bottom?
a. 5.0 m/s
c. 11 m/s
b. 10 m/s
d. She stops before she reaches the bottom.
Question 2
A cylinder containing an ideal gas has a volume of 3.0 m3 and a pressure of 1.0 105 Pa at a temperature of 300 K. The cylinder is placed against a metal block that is maintained at 900 K and the gas expands as the pressure remains constant until the temperature of the gas reaches 900 K. The change in internal energy of the gas is 9.0 105 J. Find the change in entropy of the block associated with the heat transfer to the gas.
a. 0
c. -1700 J/K
b. +670 J/K
d. -1100 J/K