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October 22, 2019, 10:21:57 am

Author Topic: Work Done against Air Friction  (Read 127 times)  Share 

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Jefferson

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Work Done against Air Friction
« on: September 15, 2019, 11:47:36 pm »
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A 10 kg rock is dropped from rest and falls vertically for 5.0 seconds. After this time, the rock was moving at 40.0 m/s. What was the work done against air friction in this time?

(A) 12 kJ
(B) 4 kJ
(C) 9 kJ
(D) 100 J

Answer is (B) 4 kJ.

Could someone help me with this?
I'm getting 1.8 kJ instead.