Momentum+and+Impulse

=The Impulse Momentum relationship = toc On this page we will be looking at the relationship between Momentum and Impulse. But before we can compare Momentum and Impulse we must first define both.

**Momentum** in physics is defined by the following equation.

 Momentum is represented as a P and is a Vector. M represents the mass of the given object and v the velocity vector of the object. Using Si units Momentum is represented in kg x m/s.

We can now modify the Momentum equation to represent the change in force required to create a specific change in momentum. This is the original form Sir. Issac Newton used to first describe the second law of motion.



 The definition of **impulse** is the following:



A very powerful combination of Momentum and Impulse into one equation can be derived from:





This equation can be very helpful in solving equations during the AP test and can be much quicker than other methods available.

=Sample Questions =

Question #1
A navy rail gun shoots an 5 Kg projectile at 750m/s. What is the momentum of the projectile?

Question #2
A model rocket is shot of a rocket pad in a field. The rocket weighs 5 Kg and the motor burn lasts for 5 seconds. If the rocket's peak velocity is 15m/s what is the Impulse of the motor?

Question #3
You are playing a game of kick ball with your friends. You kick the ball out to center field where you hit the center fielder and he is knocked over in one second. The kick ball weighs .5 Kg and was traveling at 10m/s. How much force was the player hit with?

=<span style="color: #0000ff; font-family: 'Trebuchet MS',Helvetica,sans-serif;">Question Answers =

<span style="color: #0000ff; font-family: 'Trebuchet MS',Helvetica,sans-serif;">Answer #1
In this problem we simply use the momentum equation and plug in chug to find the answer. p = mv m = 5 Kg v = 750m/s p = (5)750 = 3750Kg. m/s

<span style="color: #0000ff; font-family: 'Trebuchet MS',Helvetica,sans-serif;">Answer #2
In this we need to find impulse, but we are not given the force that was applied to the rocket. We must use the Impulse Momentum relationship to find the change in Momentum which is equal to the impulse. <span style="font-family: 'Trebuchet MS',Helvetica,sans-serif;"> p = mv 1 - mv 2 m1 = 5Kg m2 = 5Kg v1 = 15 v2 = 0 p = 5(15) - 5(0) p = 75 I = p = 75

<span style="color: #0000ff; font-family: 'Trebuchet MS',Helvetica,sans-serif;">Answer #3
To solve this problem we use Newton's second law in the new way we learned it on this page. F = pt = mvt m = 5kg v = 10m/s t = 1s F = 5(10)1 = 50 Newtons of Force

=<span style="color: #0000ff; font-family: 'Trebuchet MS',Helvetica,sans-serif;">References = [] [] []