Momentum and Energy problem, conservation.?

In summary, the conversation revolves around a pendulum experiment involving a 9.99 kg bob and a bullet of mass 0.01 kg being fired at it. The bullet embeds itself in the bob and the pendulum reaches a maximum vertical displacement of 4.60 cm. The first question asks for the velocity of the bullet before impact, to which the answer is 949 m/s. The second question involves a rubber bullet being fired at the bob with the same velocity, but this time, the collision is elastic. The question asks for the resulting vertical displacement of the pendulum, which is 18.4 cm. The solution to both questions requires the use of conservation of momentum and energy principles.
  • #1
student1234
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0

Homework Statement



A pendulum of 9.99 kg is initially at rest, just skimming the floor below. A bullet of mass 0.01kg is fired at the bob. The bullet collides with the bob and embeds itself, after which the pendulum begins to move. The bullet-bob pendulum reaches the maximum vertical displacement of 4.60 cm.

a) Calculate the velocity of the bullet just before the impact with the bob. (ANS: 949m/s)

b) If a rubber bullet of mass 0.01kg was fired at the 9.99 bob with a speed of 949 m/s, and collided elastically with the bob, how high would the pendulum now rise?

ANS b: 18.4 cm

Homework Equations



P1 = P2 and E1 = E2

The Attempt at a Solution



a) I think we are supposed to use the conservation of momentum and energy to answer this but I cannot do it.

26 minutes ago - 4 days left to answer.
 
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  • #2
You're right. You need to use conservation of momentum and energy. Show us your attempt at applying those principles.
 

Related to Momentum and Energy problem, conservation.?

1. What is momentum and energy conservation?

Momentum and energy conservation is a fundamental principle in physics that states that the total amount of momentum and energy in a closed system remains constant over time. This means that in a closed system, momentum and energy can be transferred or transformed, but the total amount remains the same.

2. How is momentum conserved in a collision?

In a collision between two objects, the total momentum of the system before and after the collision remains the same. This means that the momentum of one object may decrease, but the other object's momentum will increase by the same amount, resulting in a constant total momentum.

3. What is the difference between elastic and inelastic collisions?

In an elastic collision, both momentum and kinetic energy are conserved. This means that the objects collide and bounce off each other without any energy being lost. In an inelastic collision, some of the kinetic energy is converted into other forms of energy, such as heat or sound, and is not conserved.

4. How does conservation of energy apply to everyday life?

Conservation of energy applies to many everyday situations, such as riding a bike or driving a car. When pedaling a bike, the energy from your body is transferred to the bike, allowing it to move forward. In a car, the gasoline is converted into kinetic energy to power the car and overcome friction and air resistance.

5. Can momentum or energy be created or destroyed?

No, according to the law of conservation of momentum and energy, they cannot be created or destroyed. They can only be transferred or transformed into different forms, such as potential or thermal energy. This principle is a fundamental concept in physics and has been proven to hold true in all observed situations.

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