A bicyclist starts a timed race at $6.0 \mathrm { mi } / \mathrm { h }$ In order to win, he must average $21 \mathrm { mi } / \mathrm { h }$ Assuming constant acceleration from the start, how fast must he be traveling at the end of the race?
A)36 mi/h
B)30 mi/h
C)24 mi/h
D)42 mi/h

Question

Quizplus · Accepted Answer

To find the final velocity, use the formula for average velocity in uniformly accelerated motion: $v_{avg} = \frac{v_i + v_f}{2}$. Given $v_{avg} = 21 \, \text{mi/h}$ and $v_i = 6 \, \text{mi/h}$, solve for $v_f$: $21 = \frac{6 + v_f}{2}$, which gives $v_f = 36 \, \text{mi/h}$.

A Bicyclist Starts a Timed Race At 6.0mi/h6.0 \mathrm { mi } / \mathrm { h }6.0mi/h

A Bicyclist Starts a Timed Race At $6.0 \mathrm { mi } / \mathrm { h }$