A car is traveling north at $17.7 \mathrm {~m} / \mathrm { s }$ After 12 s its velocity is $14.1 \mathrm {~m} / \mathrm { s }$ in the same direction. Find the magnitude and direction of the car's average acceleration. A)0.30 m/s², south B)2.7 m/s², south C)0.30 m/s², north D)2.7 m/s², north

Question

Quizplus · Accepted Answer

The car's velocity is decreasing, so its acceleration must be in the opposite direction of its velocity, which is south. The magnitude of the acceleration is:$$a=\frac{\Delta v}{\Delta t}=\frac{14.1	ext{ m/s}-17.7	ext{ m/s}}{12	ext{ s}}=\boxed{0.30	ext{ m/s}^2}$$

A Car Is Traveling North At 17.7 m/s17.7 \mathrm {~m} / \mathrm { s }17.7 m/s

A Car Is Traveling North At $17.7 \mathrm {~m} / \mathrm { s }$