Gary, an online physics student, has a mass of 80.5 kg. his new bicycle has a mass of 13.7 kg. gary is pedaling so that a net (unbalanced) force of 9.86 n accelerates him and his bicycle. what is the value of the acceleration?
notice the two masses are added together because the 9.86 n force accelerates the system of masses.
m = 13.7 kg + 80.5 kg = 94.2 kg
f = 9.86 n
a = ?
f = ma
a = f/m = 9.86 n/94.2 kg
f = 0.10467 m/s2
f = 0.105 m/s2

Ahair dryer is basically a duct in which a few layers of electric resistors are placed. a small fan pulls the air in and forces it through the resistors where it is heated. air enters a 1200 w hair dryer at 100 kpa and 22°c and leaves at 47°c. the cross-sectional area of the hair dryer at the exit is 60 cm2. neglecting the power consumed by the fan and the heat losses through the walls of the hair dryer, determine (a) the volume flow rate of air at the inlet and (b) the velocity of the air at the exit.