Ablock falls from a ledge 10 m high. just before it hits the ground, its kinetic energy
a. equal to its potential energy at that point.
b. equal to zero.
c. increasing.
d. equal to its potential energy on the ledge.
e. all converted into thermal energy.
f. the same as on the ledge.

The air in an automobile tire with a volume of 2.60 ft3 is at 70°f and 21 psig. determine the amount of air that must be added to raise the pressure to the recommended value of 30 psig. assume the atmospheric pressure to be 14.6 psia and the temperature and the volume to remain constant. the gas constant of air is ru = 53.34ft⋅lbflbm⋅r(1 psia144 lbf/ft2) = 0.3704 psia⋅ft3lbm⋅r the amount of air that must be added to raise the pressure is lbm