Question
A bullet of mass 10g travelling horizontally at a speed of 100m/s embeds itself in a block of wood of mass 990g suspended by strings so that it can swing freely find:
a.the vertical height through which the block rises.
B.how much of the bullet energy becomes internal energy (g
a.the vertical height through which the block rises.
B.how much of the bullet energy becomes internal energy (g
Answers
Elena
The law of conservation of linear momentum
mv=(m+M)u
The law of conservation of energy
u =mv/(m+M) = 0.01•100/(0.99+0.01)= 1 m/s.
(m+M)u²/2 =(m+M)gh
h= u²/2•g=1/2•9.8=0.05 m
mv²/2- (m+M)u²/2 = 0.01•10000/2 - 1•1/2 = 50-0.5=49.5 J
mv=(m+M)u
The law of conservation of energy
u =mv/(m+M) = 0.01•100/(0.99+0.01)= 1 m/s.
(m+M)u²/2 =(m+M)gh
h= u²/2•g=1/2•9.8=0.05 m
mv²/2- (m+M)u²/2 = 0.01•10000/2 - 1•1/2 = 50-0.5=49.5 J