a bullet is fired normally on an immovable wooden plank. it looses 25%of its momentum in penetrating a thickness of 3.5cm.find the total thickness in cm penetrated by the bullet..
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Hey Mate
Take initial momentum (Pi)= mv
as the momentum is dropped by 25 percent, the final momentum will be
Pi-(25/100)Pi=(3/4)Pi=Pf
assuming that the mass is constant,
pf =3/4 mv = m (3/4 v)
velocity after travelling 3.5 cm = 3/4 v
from equation v²-u²=2as
(3/4)² v²-v² = 2a (3.5)
[9/16 v² - v²] / 2(3.5) = a
(-7/16 v²)/7 = a
a= -1/16 v²
now to find displacement at velocity=0
0²-v² = 2 (-1/16v²) s
1= (1/8) s
s= 8 cm
hope this answer helps you
Take initial momentum (Pi)= mv
as the momentum is dropped by 25 percent, the final momentum will be
Pi-(25/100)Pi=(3/4)Pi=Pf
assuming that the mass is constant,
pf =3/4 mv = m (3/4 v)
velocity after travelling 3.5 cm = 3/4 v
from equation v²-u²=2as
(3/4)² v²-v² = 2a (3.5)
[9/16 v² - v²] / 2(3.5) = a
(-7/16 v²)/7 = a
a= -1/16 v²
now to find displacement at velocity=0
0²-v² = 2 (-1/16v²) s
1= (1/8) s
s= 8 cm
hope this answer helps you
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