Determine Initial Velocity of Projectile with Ballistic Pendulum

In summary, the conversation discusses the use of a ballistic pendulum to determine the initial velocity of a projectile with a mass of 0.010kg. The pendulum reaches a height of 0.65 m/s after the collision. The concepts involved are conservation of momentum and energy. The individual asking for help believes the answer is Vi=3.6m/s, but it is incorrect and the responder reminds them to use conservation of momentum instead of energy. The initial velocity of 3.6 m/s is deemed unrealistic for a bullet.
  • #1
uvburgos
4
0
The ballistic pendulum is a block with the mass 2.50kg suspended on a cable, the projectile has a mass of 0.010kg and is shouted with the initial velocity, after the collision the pendulum reach the height of h=0.65 m/s. Determine the initial velocity of the projectile.
 
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  • #2
Hi uvburgos and welcome to PF,

What are your thoughts on the question? Which concepts are involved? Have your read your class notes on the concepts involved?
 
  • #3
I do have the answer just need verify is my answer is correct (Vi=3.6m/s)
 
  • #4
uvburgos said:
I do have the answer just need verify is my answer is correct (Vi=3.6m/s)
No, I'm afraid your answer is incorrect.

Reality check: Does 3.6 m/s seem like a realistic velocity for a bullet?
 
  • #5
I forget to write at the end to ignore the friction
 
  • #6
uvburgos said:
I forget to write at the end to ignore the friction
This doesn't change the answer. Your solution is still incorrect, conservation of energy does not apply here. You must you conservation of momentum.
 

1. How does a ballistic pendulum work?

A ballistic pendulum is a device used to determine the initial velocity of a projectile. It works by allowing a projectile to strike a pendulum and measuring the resulting swing of the pendulum. The momentum of the projectile is transferred to the pendulum, causing it to swing to a certain height. By measuring this height and using the principle of conservation of momentum, the initial velocity of the projectile can be calculated.

2. What is the principle of conservation of momentum?

The principle of conservation of momentum states that in a closed system, the total momentum remains constant. This means that the initial momentum of a system is equal to the final momentum, regardless of any internal forces or collisions that may occur. In the case of a ballistic pendulum, the initial momentum of the projectile is equal to the final momentum of the pendulum.

3. How is the initial velocity of the projectile calculated using a ballistic pendulum?

The initial velocity of the projectile can be calculated by using the equation: m1v1 = (m1 + m2)v2. In this equation, m1 is the mass of the projectile, v1 is the initial velocity of the projectile, m2 is the mass of the pendulum, and v2 is the final velocity of the pendulum. By rearranging this equation, the initial velocity of the projectile can be calculated as v1 = (m1 + m2)v2 / m1.

4. What are the limitations of using a ballistic pendulum to determine initial velocity?

There are a few limitations to using a ballistic pendulum. The pendulum must be able to swing freely and without friction, which may not always be possible to achieve. The projectile must also strike the pendulum in the center of mass, and the pendulum must be able to absorb the entire momentum of the projectile without breaking. Additionally, air resistance and other external factors may affect the accuracy of the measurement.

5. Are there any real-life applications of using a ballistic pendulum?

Yes, the principle of a ballistic pendulum is used in various fields such as forensic science, ballistics, and engineering. It can be used to determine the velocity of a bullet, arrow, or other projectile. It can also be used to measure the muzzle velocity of firearms and to study the effects of different materials on the speed and force of impact.

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