In a braking test, a vehicle travelling at a speed of 36 kmph was stopped by applying brakes fully and skid marks were 4.0 m in length. Determine the average skid resistance of the pavement surface. Assume g = 10 m/sec 2.
- A1.25Correct
- B1.30
- C1.35
- D1.40
Solution
Concept
Skid test
Formula
f = v²/2gl
Step-by-step solution
1. v = 10 m/s. 2. f = 100/(2 × 10 × 4) = 1.25.
Explanation
Work–energy.
Why the other options are wrong
Others do not follow.
Shortcut
v²/2gl.
Correct answer: A) 1.25