A car moving with a speed of 90kmh\(^{-1}\) was brought uniformly to rest by the application of the brakes in 10s. How far did the car travel after the brakes were applied?
-
125m
- 150m
- 250m
- 15km
The correct answer is: A
Explanation
speed = \(\frac{90 \times 10^3}{3600}\) = 25ms\(^{-1}\)
Acceleration = \(\frac{\text{velocity change}}{\text{time}}\) = \(\frac{25}{10}\)
: Acceleration = 2.5
Using S = Ut + \(\frac{1}{2}\) at\(^2\)
S = \(\frac{1}{2}\) X 2.5 X 10\(^2\) = 125m