6) In a purely electric vehicle, energy usually is stored in batteries. The stored energy is used to power the vehicle until the energy is depleted, and then energy has to be stored once more by
recharging the batteries. An electric wheelchair has a mass of 26 kg and is custom–designed for a
person with a mass of 80.0 kg. The stored energy available in its batteries is 2.4106
J. The
wheelchair motor requires a power of 340.0 W for driving under typical conditions. This is
sufficient to propel the person in the wheelchair along at a speed of 24 km/h.
a. Determine the work done by the motor when the wheelchair starts at rest and speeds up to
its normal speed.

b. Determine the maximum distance that the wheelchair can travel on a horizontal surface at its
normal speed, using its stored energy. (Ignore the energy needed for it to speed up when it
starts.)

c. Suppose that 0.023 percent of the power required for driving is expended against drag due
to the flexing of the wheelchair’s soft rubber tires. Calculate the magnitude of the drag force.