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CBSE Class 9 Answered

if a gun of 20g fires a bullet . if the bullet pierces two coins at a distance of 30 m . at t=4seconds . assuming the speed to be constant. what is the k.e.of the gun?
Asked by ayush kumar | 04 Dec, 2010, 11:09: PM
answered-by-expert Expert Answer
Dear student
v = u + at
here, u=0
so, a = v/t
Again , s = ut + at2
or, s = (v/t)t2 = vt
or, v = s/t= 30 /4 = 7.5 m/s
Therefore, K.E. = (1/2)mv2  = (1/2) (20/1000) (7.5)2 = 0.56 J
We hope this clarifies your doubt.
Regards
Team
Topperlearning
Answered by | 06 Dec, 2010, 12:09: PM

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