A racecar driver speeds up from 60 miles per hour to 90 miles per hour in 3 seconds. What was his/her acceleration in mph/sec?

Choose the best answer from the options below:
A 10
B 20
C 30
D 40
E 50

1 answer

To find the acceleration, we can use the formula:

acceleration = (change in velocity) / (change in time)

The change in velocity is 90 - 60 = 30 mph, and the change in time is 3 seconds.

acceleration = 30 mph / 3 sec = 10 mph/sec

Therefore, the acceleration in mph/sec is 10.

The correct answer is A.