A vehicle moving at 54 kmph speed was stopped by applying a brake and the length of the skid marks was 25 m. If the average skid resistance of the pavement is known to be 0.50, then determine the brake efficiency of the test vehicle. Assume g = 10 m/sec 2.
- A88%
- B90%Correct
- C92%
- D94%
Solution
Concept
Brake efficiency
Formula
η = factual / fmax
Step-by-step solution
1. v = 15 m/s; f = 225/(2 × 10 × 25) = 0.45. 2. η = 0.45/0.5 = 90%.
Explanation
Ratio of measured to ideal deceleration.
Why the other options are wrong
Others do not follow.
Correct answer: B) 90%