An initially motionless test car is accelerated uniformly to 105 km/h in 8.78 se
ID: 1433522 • Letter: A
Question
An initially motionless test car is accelerated uniformly to 105 km/h in 8.78 seconds before striking a simulated deer. The car is in contact with the faux fawn for 0.935 seconds, after which the car is measured to be traveling at 71.0 km/h. What is the magnitude of the acceleration of the car before the collision?
What is the magnitude of the average acceleration of the car during the collision?
What is the magnitude of the average acceleration of the car during the entire test, from when the car first begins moving until the collision is over?
Explanation / Answer
105 kmph
105*5/18 = 29.167 m/s
acceleration of the car before collision = 29.167 / 8.78 = 3.32 m/s2
71 kmph = 71*5/18 = 19.72 m/s
magnitude of average acceleration during the collision = dv/dt = 29.167 - 19.72 / 0.935 = 10.1 m/s2
magnitude of average acceleration of the car = 29.167 - 19.72 / (8.78 + 0.935) = 0.972 m/s2