JEE Class main Answered
A rifle bullet loses 1/20th of its velocity in passing through a plank.find how many such uniform planks it would pass through before coming to rest assuming resistance to the plank to be uniform
Asked by Sunita | 06 Jun, 2019, 11:37: PM
Expert Answer
If v is initial velocity of bullet, after loosing (1/20)th of initial velocity due to passing through wooden plank of depth d,
velocity of bullet becomes (19/20)v .
Retardation a created by wooden plank can be obtained from, " V2 = U2 - 2aS ", where V is final speed,
U is initial speed, S is the ditance travelled and a is retardation.
hence we have, (19/20)2 v2 = v2 - (2×a×d ) or a = (39/400)v2/ (2d) ..........................(1)
if final velocity of bullet is zero after passing through depth D, then we have, 0 = v2 - (2×a×D) ..........................(2)
By substituting retardation a from eqn.(1) in eqn.(2), we get, v2 = [(39/400)v2/ d ]×D or D/d = 400/39 ≈ 10
Hence 9 more planks of same depth d is required to stop the bullet
Answered by Thiyagarajan K | 07 Jun, 2019, 09:38: AM
Application Videos
-
Elastic potential energy_Restoring force and spring con ...
In this video, the restoring force and spring constant is explained. The vi... -
Expression of Elastic potential energy_2
This video describes the potential energy of spring when it is compressed o... -
Potential Energy Curve
This video describes the potential energy curve and ature of forces based o... -
Work done by static friction
This video describes effect of static friction on the work done by the obje... -
Work done in conservative field - 1
The concept of conservative field, types of conservative forces and example...
JEE main - Physics
Asked by mohammedimroz | 13 Apr, 2024, 09:48: PM
ANSWERED BY EXPERTJEE main - Physics
Asked by medhamahesh007 | 02 Apr, 2024, 11:11: AM
ANSWERED BY EXPERTJEE main - Physics
Asked by gundlasumathi93 | 31 Mar, 2024, 02:13: PM
ANSWERED BY EXPERTJEE main - Physics
Asked by chhayasharma9494 | 31 Mar, 2024, 12:47: PM
ANSWERED BY EXPERTJEE main - Physics
Asked by archithateja3 | 30 Mar, 2024, 10:23: PM
ANSWERED BY EXPERTJEE main - Physics
Asked by Machinenineha | 27 Mar, 2024, 05:28: PM
ANSWERED BY EXPERT
JEE main - Physics
Asked by mfkatagi099 | 20 Mar, 2024, 09:35: PM
ANSWERED BY EXPERTJEE main - Physics
Asked by sreelekhachakali2006 | 15 Mar, 2024, 10:35: AM
ANSWERED BY EXPERT
