A common statistic in car tests is the standing (starting from rest)quarter-mile performance.A modern sports car can achieve a terminal speed (speed at the end of the quarter-mile)of 120 mph (193 km/h).How does the average acceleration compare to g? (0.25 mile = 402 m)
A)0.36 g
B)2.8 g
C)0.067 g
D)15.0 g
E)0.73 g

Question

Quizplus · Accepted Answer

The average acceleration can be calculated using the formula for acceleration $a = \frac{v^2}{2s}$, where $v$ is the final velocity in meters per second (m/s) and $s$ is the distance in meters (m). First, convert 120 mph to m/s: $120 \times 0.44704 = 53.645 \text{ m/s}$. Then, plug the values into the formula: $a = \frac{(53.645)^2}{2 \times 402} = 3.57 \text{ m/s}^2$. The acceleration due to gravity ($g$) is approximately $9.81 \text{ m/s}^2$, so the average acceleration in terms of $g$ is $3.57 / 9.81 = 0.36 g$.

A Common Statistic in Car Tests Is the Standing (Starting