Solving Collision Problem: 10.0g Bullet & 5.00lg Block

  • Thread starter Dejey
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In summary, a 10.0-g bullet, with an unknown original speed, is fired into a stationary block of wood with a mass of 5.00 kg. The bullet becomes embedded in the block and the combined speed of the two immediately after the collision is 0.600 m/s. The given equation, v= (m1)(v1a)/((m1)+(m2), is not applicable for finding the original speed of the bullet. Instead, the conservation of momentum equation should be used and rearranged to solve for the bullet's original speed.
  • #1
Dejey
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Homework Statement


a 10.0-g bullet is fired into a stationary block of wood (m=5.00 lg). the bullet imbeds into the block. the speed of the bullet-plus-wood combination immediately after the collision is 0.600 m/s. what was the original speed of the bullet


Homework Equations



v= (m1)(v1a)/((m1)+(m2)
I=delat p
i am not 100% if you would even use that, or if that is what you need. i tryed it out and i will post it in about 10min. but the answer was given to me, and when i tested it out, i was wrong

The Attempt at a Solution



to be added soon.
 
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  • #2
Dejey said:
v= (m1)(v1a)/((m1)+(m2)

If you tried to work out the answer using this then you would be wrong. You're trying to find the speed of the bullet. the equation you've given is arranged for the speed of the bullet and block which you already know. Start with the conservation of momentum equation and try rearranging it again.
 
  • #3


I would approach this problem using the principle of conservation of momentum. This principle states that the total momentum of a closed system remains constant before and after a collision. In this case, the bullet and the block form a closed system, so we can use this principle to solve for the original speed of the bullet.

First, we need to calculate the total mass of the bullet-plus-wood combination. We know that the mass of the bullet is 10.0 g, which is equal to 0.010 kg. The mass of the block is given as 5.00 lg, which is equal to 0.00500 kg. Therefore, the total mass of the system is 0.010 kg + 0.00500 kg = 0.0150 kg.

Next, we can use the conservation of momentum equation: m1v1 = (m1 + m2)v2, where m1 is the mass of the bullet, v1 is the original speed of the bullet, m2 is the mass of the block, and v2 is the final speed of the bullet-plus-wood combination.

Plugging in the values, we get: (0.010 kg)(v1) = (0.010 kg + 0.00500 kg)(0.600 m/s). Solving for v1, we get v1 = (0.0150 kg)(0.600 m/s) / 0.010 kg = 0.0900 m/s.

Therefore, the original speed of the bullet was 0.0900 m/s. This approach uses the principle of conservation of momentum, which is a fundamental concept in physics. I hope this helps to solve the problem and understand the underlying principle behind it.
 

1. How do you calculate the velocity of the bullet and block after the collision?

The velocity of the bullet and block after the collision can be calculated using the conservation of momentum formula, where the initial momentum of the bullet (mass x initial velocity) is equal to the final momentum of the bullet and block (mass x final velocity).

2. How does the mass of the bullet and block affect the collision?

The mass of the bullet and block will affect the collision by determining the amount of momentum each object has. A larger mass will result in a greater momentum, which can lead to a more significant change in velocity after the collision.

3. What is the role of kinetic energy in a collision?

Kinetic energy is important in a collision because it determines how much energy is transferred between the objects involved. In a perfectly elastic collision, the kinetic energy remains the same before and after the collision, while in an inelastic collision, some kinetic energy is lost as heat or sound.

4. How does the angle of impact affect the collision?

The angle of impact can affect the collision by changing the direction of the objects' velocities after the collision. For example, if the bullet hits the block at a 90-degree angle, the block will have a velocity in the opposite direction of the initial bullet's velocity.

5. Can you predict the outcome of a collision between a bullet and a block?

Yes, the outcome of a collision can be predicted by using the conservation of momentum and energy principles, as well as considering other factors such as the mass and angle of impact. However, there may be unforeseen variables that can affect the outcome, so it is not always possible to predict with 100% accuracy.

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