Calculate the momentum of a body of mass 450 g moving with a speed of 120 km/h.
5. A bullet of mass 20 g travelling with a velocity of 20 m/s penetrates a sand bag and comes to rest in
0.05 second. Find a) the distance through which it penetrates b) retarding force.
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Answered by
0
Answer:
speed of 120 km/h.
mass 450
bullet of mass 20 g
0.05 second.
speed=d/t
d=speed *time
120*0.05
Answered by
0
Answer:
Answered October 13, 2017
Mass of bullet(m)= 30g = 0.03kg.
Initial velocity (u)= 400m/s.
Final velocity (v)= 0m/s. [Since bullet comes to rest after penetrating 10 cm in wall]
Distance penetrated by bullet (S) or displacement of bullet in presence of resistive force = 10 cm = 0.1m.
Acceleration (a)=?
From third equation of motion:
v^2=u^2+2aS
0^2= 400^2+2a*0.1
0.2a=-160000
a=-160000/0.2= -8,00,000m/s^2.
The negative sign shows that acceleration takes place in direction opposite to the initial direction of motion of bullet or retardation takes place.
Avg. force (f)= m*a
f= 0.03*-800000
f= -24000N
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