Question

A car starts from rest and accelerates uniformly to a speed of 72km/hr over a distance of 500m. Find the acceleration of the car and time taken to attain this speed

Answer 1

Answer: a = 0.4 m/s^2

t = 50 s

Explanation:

Convert 72 km/hr to m/s by multiplying it by (1000 m / 1 km)(1 hr / 3600s).

Then, plug this into the formula: (v final)^2 = (v original)^2 + 2*a*d; v original = 0, so it becomes 20^2 = 2*a*500. This yields a = .4 m/s^2.

For the time: a = change in speed / t, which becomes .4 = 20 / t, which yields t = 50 s.