What is the kinetic energy of a 20 kg body moving at 9 m/s?
Answer and explanation
Correct answer: B. 810 J
- Step 1: KE = ½mv². Step 2. KE = ½ × 20 × 9² = 810 J. Answer: 810 J. Why not the others: 1620 J is what you get if you forget the factor ½. 90 J is what you get if you forget to square the speed. 405 J is what you get if you halve twice.
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