The decrease in the potential energy of a ball of mass 20 kg which falls from a height of 50 cm is:
Correct answer: C. 98 J
- A. 968 J
- B. 1980 J
- C. 98 J
- D. None of these
Explanation
To calculate the potential energy of the ball, we can use the formula for gravitational potential energy: Potential Energy (PE) = mass (m) * acceleration due to gravity (g) * height (h) Given: mass (m) = 20 kg height (h) = 50 cm = 0.5 m acceleration due to gravity (g) ≈ 9.81 m/s² (standard value) Now, let's calculate the potential energy: PE = m * g * h PE = 20 kg * 9.81 m/s² * 0.5 m PE ≈ 98.1 J So, the potential energy of the ball at a height of 50 cm is approximately 98.1 joules.
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Work transfers energy when a force causes displacement, while kinetic energy, gravitational potential energy and power describe motion, position and the rate of energy transfer. The work-energy theorem links net work with change in kinetic energy, and efficiency accounts for energy losses rather than treating them as energy destruction.
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