Collisions and Change in Momentum

In summary, the ball of mass 4.7 kg, initially moving in the x-direction with a speed of 1.9 m/s, bounces off a wall with the same speed in the opposite direction. The change in momentum of the ball is -2P and it is directed towards the -x direction.
  • #1
jabbie3
19
0

Homework Statement



A ball of mass 4.7 kg moving with speed of 1.9 m/s in the x-direction hits a wall and bounces back with the same speed in the -x-direction. What is the change of momentum of the ball? And in what direction?

Homework Equations



p=mv

The Attempt at a Solution



P=mv
P=4.7*1.9
P=8.93
 
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  • #2
So what is the initial momentum?

What is the final momentum?

What is the difference?
 
  • #3
The initial is 8.93 and the final is -8.93..so total momentum is 0? In what direction?
 
  • #4
Try again using pf - pi to find the difference.
 
  • #5
jabbie3 said:
The initial is 8.93 and the final is -8.93..so total momentum is 0? In what direction?

Sorry, signs matter.

Initial momentum = P
Final momentum = -P

Final - initial = Δ = (-P) - P = -2P

Negative because Δx/Δt is toward -x.
 

FAQ: Collisions and Change in Momentum

What is momentum?

Momentum is a measure of an object's motion, calculated by multiplying its mass by its velocity. It is a vector quantity, meaning it has both magnitude and direction.

How is momentum conserved in a collision?

In a closed system, the total momentum before a collision is equal to the total momentum after the collision. This is known as the law of conservation of momentum. This means that the sum of all the momenta of the objects involved in the collision will remain constant.

What is an elastic collision?

An elastic collision is a collision in which both momentum and kinetic energy are conserved. This means that after the collision, the objects involved will continue to move at the same speed and in the same direction as before the collision.

How does mass affect the change in momentum?

The change in momentum is directly proportional to the mass of the object. This means that a larger mass will experience a greater change in momentum compared to a smaller mass when subjected to the same force.

What is the difference between momentum and impulse?

Momentum is a measure of an object's motion, while impulse is a measure of the change in an object's momentum. Impulse is equal to the force applied to an object multiplied by the time it is applied for. In other words, impulse is the amount of change in momentum an object experiences due to a force acting on it for a specific amount of time.

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