Why it is 85 J ?
更新1:
the height of the slope is 3 meter
physics mechanics
2009-04-19 2:04 am
an object of mass 2 kg is projected down a rough inclined plane with a speed 5m/s. The object stops at of the plane. Find the work done against friction in the journey. ( Neglect the size of the object)
Why it is 85 J ?
Why it is 85 J ?
回答 (2)
2009-04-19 6:57 am
✔ 最佳答案
There are missing information such as time or distance traveled.2009-04-18 22:57:43 補充：
The kinetic energy before the slip = 1/2 * 2 * 5^2 = 25 J
The potential energy before the slip = 2 * 10 * 3 = 60 J
Since the object stops at the end of the slop, all energy is consumed by friction. Therefore, the work done due to friction is 25 J + 60 J = 85 J
Note that gravitational acceleration used is 10 instead of 9.8. If you use 9.8, you will get 83.8 J instead.
2009-04-19 4:33 am
I want to ask if there are any things or information missing such as time(t) ?
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https://hk.answers.yahoo.com/question/index?qid=20090418000051KK01584