In the Soapbox Derby in (Figure 1) , young participants build non-motorized cars
ID: 1276395 • Letter: I
Question
In the Soapbox Derby in (Figure 1) , young participants build non-motorized cars with very low-friction wheels. Cars race by rolling down a hill. Assume that the track begins with a 49-ft{ m ft}-long (1 m{ m m} = 3.28 ft{ m ft}) section tilted 15 degrees below horizontal.
A)
What is the maximum possible acceleration of a car moving down this stretch of track?
Express your answer to two significant figures and include the appropriate units.
B)
If a car starts from rest and undergoes this acceleration for the full l , what is its final speed in m/s ?
Express your answer using two significant figures.
Explanation / Answer
a) What is the maximum possible acceleration of a car moving down this stretch of track?
Fnet= Fgravity
=> amax = mgravity x sin(13)
=>amax = 9.8 x 0.22
= 2.20 m/sec2
b) If a car starts from rest and undergoes this acceleration for the full l, what is its final speed in m/s?
55 feet converted to meters = 16.76 meters
v2 = u2 + 2as
=>v2 = 0 + 2 x 2.20 x 16.76
=>v = ? (73.74)
= 8.59 m/s