A mass of 20kg produces a momentum of 300kgm/s. What is the Kinetic energy?
- 4500 Joules.
- 2250 Joules.
- 3250 Joules.
Explanation
Momentum p = mv, so velocity = 300 / 20 = 15 m/s. Kinetic energy is half mass times velocity squared: 0.5 x 20 x 15 x 15 = 2250 Joules. A useful shortcut is KE = p squared divided by 2m = 90000 / 40 = 2250 J.
romeshkunder asking:
please explain
Community Comments (1)
D
dimky Posts: 514 31.08.2013 / 10:25
Momentum = MV
300 = 20V
V = 15
KE = 1/2MV^2 = 1/2*20*15*15 = 2250J.
300 = 20V
V = 15
KE = 1/2MV^2 = 1/2*20*15*15 = 2250J.
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