A 40kg body starting from rest falls through a vertical distance of 125cm to the ground. The velocity of the body just before it hits the ground is:
Correct answer: D. 5 m/s
- A. 250 m/s
- B. (250)½ m/s
- C. 25 m/s
- D. 5 m/s
Explanation
Convert 125 cm to meters: 125 cm = 1.25 mUse the kinematic equation: v² = u² + 2as, where:v = final velocity (what we want to find)u = initial velocity (0 m/s, since it starts from rest)a = acceleration (g = 9.8 m/s², acceleration due to gravity)s = displacement (1.25 m)v² = 0² + 2 * 9.8 m/s² * 1.25 mv² = 24.5 m²/s²v = √24.5 m²/s² ≈ 4.95 m/s, which is closest to 5 m/s.Therefore, this option is correct.
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