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salantis [7]
3 years ago
11

A 15g bullet is fired horizontally into a 3kg block of wood suspended by a long cord. Assume that the bullet remains in the bloc

k and that it swings 0.086m above the initial height. Calculate the velocity of the bullet when it strikes the wood.
Physics
1 answer:
Varvara68 [4.7K]3 years ago
5 0

Answer:

261.3 m/s

Explanation:

Mass of bullet=m=15 g=\frac{15}{1000}=0.015 kg

1 kg=1000g

Mass of block=M=3 kg

d=0.086 m

Total mass =M+m=3+0.015=3.015 kg

K.E at the time strike=Gravitational potential energy at the end of swing

\frac{1}{2}(m+M)^2V^2=(m+M)gh

Using g=9.8m/s^2

Substitute the values

\frac{1}{2}(3.015)V^2=3.015\times 9.8\times 0.086

V^2=\frac{2\times 3.015\times 9.8\times 0.086}{3.015}

V=\sqrt{2\times 3.015\times 9.8\times 0.086}}

V=1.3m/s

Velocity after collision=V=1.3 m/s

Velocity of block=v'=0

Using conservation law of momentum

mv+Mv'=(m+M)V

Using the formula

0.015v+3(0)=3.015(1.3)

0.015v=3.015(1.3)

v^2=\frac{3.015(1.3)}{0.015}=261.3

v=261.3 m/s

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Explanation:

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Answer:

v = 12.1 m/s

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  • Now, we know that the centripetal force is related with the tangential speed at this point and the radius of the circle as follows:

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  • Since the normal force takes any value as needed to make (1) equal to (2),  if the speed diminishes, it will be needed less force to keep the equality valid.
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