Calculating Bullet Velocity using Frictional Force and Block Displacement

  • Thread starter runningirl
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In summary, the conversation discussed an experiment to determine the velocity of a bullet fired from a rifle. By firing the bullet into a block of wood and measuring the distance it travels and the frictional force present, the velocity of the bullet can be calculated using the equations f=ma, j=Fave(t), P=m(v), and d=(Vf^2-Vo^2)/2a. It was determined that the bullet had a velocity of approximately 0.45 m/s.
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runningirl
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Homework Statement



You have been asked to determine the velocity with which a certain rifle fires its 2.0 g bullets. You are limited in equipment and so decide to set up the following experiment. You fire the bullet into a 0.50 kg block of wood which is resting on a tabletop. The bullet lodges in the bullet and the block slides 0.36 m across the tabletop before coming to a stop. You then determine that the frictional force between the block and the tabletop is 1.4 N. Use these data to determine the velocity of the bullet.

Homework Equations



f=ma
j=Fave(t)
P=m(v)
d=(Vf^2-Vo^2)/2a

The Attempt at a Solution



so i thought i could find the acceleration of the block by doing:
2.5(a)=1.4
a=.56 m/s/s

d=(Vf^2-Vo^2)/2a

.36=v^2/.56
v=.45 m/s?
 
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  • #2
mass of bullet is 2 g and that of block is 0.5 kg...so mass of the bullet would be 0.002 kg
you made mistake while adding masses
 

1. What is momentum in physics?

Momentum is a physical quantity that describes the motion of an object. It is defined as the product of an object's mass and its velocity. In simpler terms, momentum is a measure of how difficult it is to stop an object that is moving.

2. How is momentum related to Newton's laws of motion?

Momentum is directly related to Newton's second law of motion, which states that the net force acting on an object is equal to the product of its mass and acceleration. This means that if an object has a larger momentum, it will require a larger force to change its motion.

3. Can momentum be conserved?

Yes, according to the law of conservation of momentum, the total momentum of a closed system remains constant. This means that in a closed system, the total momentum before an event must be equal to the total momentum after the event.

4. How is momentum calculated?

The momentum of an object can be calculated by multiplying its mass by its velocity. The formula for momentum is p = m x v, where p is momentum, m is mass, and v is velocity. Momentum is measured in units of kg*m/s.

5. How does momentum affect collisions?

In a collision between two objects, the total momentum before the collision is equal to the total momentum after the collision. This means that the momentum of one object will change if the momentum of the other object changes. In elastic collisions, both momentum and kinetic energy are conserved, while in inelastic collisions, only momentum is conserved.

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