bullet of mass 25 g moving with an initial velocity 250 m/s, strikes a wooden
block and comes to rest after penetrating distance 4 m in it. Calculate: (i) initial
momentum of the bullet, (ii) final momentum of the bullet, (iii) retardation caused
by the wooden block, (iv) resistive force exerted by the wooden block.
Answers
Answer:
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Answer:
Explanation:
mass of bullet ( m ) = 25 g = 25/1000 kg
initial velocity ( u ) = 250 m/sec
final velocity ( v ) = 0 m/sec { finally bullet came to rest }
displacement ( s ) = 4 m
( i ) initial momentum = mass × initial velocity
= 25/1000 × 250 = 25/4 = 6.25 kg m/sec
( ii ) final momentum = mass × final momentum
= 25/1000 × 0 = 0 kg m/sec
(iii) retardation
by third equation of motion
⇒ 2 as = v² - u²
⇒ 2 as = 0² - 250²
⇒ 2×a× 4 = -62500
⇒ 8 a = -62500
⇒ a = -62500 /8 = -78187.5 m/sec² { - sign show negative acceleration }
(iv) force = mass × acceleration
= 25/1000 × 781875/10 = 1954.6875 N
hope it helps you very well