Question

A motoris st enters a freeway at a speed of 35 mi/h and accelerates uniformly to a speed of 55 mi h. The motorist travels 500 ft while accelerating. I Determine: ) The acceleration of the car 2) The time required to reach 55 mi/h.

Answer 1

1) The acceleration of the car = 1.17 m/s²

2) The time required to reach 55 mi/h = 7.59 seconds.

Step-by-step explanation:

1) Initial speed of motorist, u = 35 mph = 15.56 m/s

Final speed of motorist, v = 55 mph = 24.44 m/s

Distance traveled, s = 500ft = 152.4 m

We have v² = u² + 2as

24.44² = 15.56² + 2 x a x 152.4

a = 1.17 m/s²

The acceleration of the car = 1.17 m/s²

2) We have v = u + at

24.44 = 15.56 + 1.17 x t

t = 7.59 s

The time required to reach 55 mi/h = 7.59 seconds.