Physicsmedium · Past Paper
A car moving at 20 m/s comes to rest in 5s after applying brakes. The retardation is:
A4 m/s^2
B-4 m/s^2
C100 m/s^2
D5 m/s^2
✓ Correct Answer: A — 4 m/s^2
a = (0 - 20) / 5 = -4 m/s^2. Retardation is the magnitude of negative acceleration, which is 4 m/s^2.
Share this question
More from Physics
- What is the shape of the wavefront for light coming from a very distant star?
- In a periscope, the two plane mirrors are placed:
- What is the work done by a person in lifting a 2 kg mass to a height of 5 m? (g=9.8 m/s^2)
- A device used to protect electrical circuits from overcurrent is called a:
- The rate of change of displacement is called: