Topic: Engineering Mechanics
In an accident site, tyre marks shows that a car was travelling along straight level street skidded for a total distance of 23 m, after the brakes applied. The coefficient of friction between the tyre and road estimated to be 0.5, what was the probable speed of car when break applied.
- A. 54 kmph
- B. 60.7 kmph
- C. 45.3 kmph
- D. 97 kmph
Answer: A. 54 kmph
Explanation: Deceleration a = -mu * g = -0.5 * 9.81 = -4.905 m/s². Using v² - u² = 2as, 0 - u² = 2 * (-4.905) * 23. u² = 225.63 => u = 15.02 m/s. In kmph, u = 15.02 * 3.6 = 54.07 kmph, which is approximately 54 kmph.