In the Soapbox Derby, young participants build non-motorized cars with very lowfriction wheels. Cars race by rolling down a hill. The track at Akron's Derby Downs, where the national championship is held, begins with a 55 -ft-long section tilted $13^{\circ}$ below hori- $-$ -low hori-ted $13^{\circ}$ below hor
zontal.
a. What is the maximum possible acceleration of a car moving down this stretch of track?
b. If a car starts from rest and undergoes this acceleration for the full $55 \mathrm{ft}$, what is its final speed in $\mathrm{m} / \mathrm{s}$ ?