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

Answer:

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

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

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.