Question

I need help
A driver starts his parked car and within 6.0 seconds, reaches a velocity of 54.0 km/h. What is his acceleration, in m/s2?

Answer 1

Answer:

5 m/s²

Explanation:

u = 0

v = 54 km/h = 54×1000/60×60 = 540/18 = 270/9

= 30 m/s

t = 6 s

a = v-u/t

= 30-0/6

= 30/6

= 5 m/s²

Answer 2

Answer:

The acceleration of the car is 2.5 m/s².

Explanation:

The driver starts the car which is parked.

Then the initial velocity of the car, u = 0 m/s

The final velocity of the car is given as, v = 54 Km/hr = 15 m/s

Time taken by the car to make this change in velocity, t = 6 s

The acceleration of the car can be found using the 1st equation of motion.

  v = u + at

⇒ a = (v - u) / t

   a = (15 - 0) / 6

   a = 2.5 m/s²