Ignoring details associated with friction, extra forces exerted by arm and leg muscles, and other factors, we can consider a pole vault as the conversion of an athlete's running kinetic energy to gravitational potential energy. If an athlete is to lift his body 5m during a vault, what speed must he have when he plants his pole?
Correct answer: B. 10 m/s
- A. 5 m/s
- B. 10 m/s
- C. 15 m/s
- D. 20 m/s
Explanation
Given: Distance = S = 5m Acceleration = a = g = 10ms-2 Initial velocity = Vi = 0 ms-1 Final velocity = Vf = ? Using third equation of motion: 2aS = Vf² - Vi² Vf² = 2aS + Vi² = 2 × 10 × 5 + (0)² Vf² = 100 Taking square root on both sides, we get: Vf = 10ms-1
This question appeared on the UHS MDCAT 2022 paper, which you can sit online with every answer explained.
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