A bullet with a mass of 0.01 kg is tired horizontally into a block of wood hanging on a string. The bullet sticks in the wood and causes it to swing upward to a height of 0.1 m. If the mass of the wood block is 2 kg, what was the initial speed of the bullet?
The initial speed of the bullet.
Answer to Problem 2C
The initial speed of the bullet is
Explanation of Solution
Given:
Given that a bullet with a mass of
Formula used:
According to the law of conservation of momentum, when the two objects collide in an isolated system, the total momentum before and after the collision is same.
Calculation:
Given that the bullet sticks in the wood and swing upward to a height of
Thus, kinetic energy of bullet is converted into the potential energy
Now, kinetic energy of combined mass just after the impact is calculated as
We have
Substituting the value in above formula, we get
Also, potential energy of wood and bullet together is calculated as
We have
Substituting the value in above formula, we get
Equating Eq(1) and Eq(2), we get
The impact of bullet on wooden block is an inelastic collision, thus momentum is conserved.
Using the conservation of momentum, we have
We have
Substituting the values, we have
Conclusion:
Hence, the initial speed of the bullet is
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Chapter 3 Solutions
Inquiry into Physics
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