Lab-9

Group 9

Nikki Sude Chris Ramasco Joey Cahill Sarah Hanrahan Pd 8 Date Done: Date Due: 2/8/10


 * Objective:** How does the impulse of a softball on a compare to the impulse of the box on the softball?


 * Hypothesis:** The impulse of the softball on a box is greater than the impulse of the box on the softball. this is due to the velocity of the softball. The masses are different and the box is not moving when the collide.


 * Data:**

Work = friction force x distance = (5.2)*(.154)(1) = .8 J
 * Calculations:**

Kinetic Energy – Work = 0 Kinetic Energy = Work = friction force * distance * cos = (5.2)*(.154)*(1) = .8 J

Velocity = KE= ½ mv2 .8= ½(1.585)*v2 1.6= (1.585)v2 1.00946= v2 1.005 m/s = v

Impulse of box-ball = mv = (1.58)*(1.005) = 1.59 kg m/s

Impulse of ball only = Impulse of box ball = 1.59 kg m/s

Initial Velocity of ball = Impulse Impulse = mv 1.59= (.185)vi vi= 8.59 m/s

Percent Difference __|measurement-calculation|__ avg *100

__|9.4-8.59|__ 13.29 *100

=6.09%

Our hypothesis agreed with our date because the impulse of the softball on the box is greater than the impulse of the box on the softball. this is due to the velocity of the softball. The masses are different and the box is not moving when the collide.
 * Conclusion Part 1:**


 * Discussion Questions:**

In order to complete the calculations in this experiment we assumed that momentum and impulse are proportional. We are also assuming that the acceleration is constant throughout, and kinetic energy is equal to the frictional force. We also knew that the change in momentum of the box on the ball would be negative, so we assumed that the momentum of the ball positive. Instead of calculating the initial velocity using energy, momentum, or conservation we could have used kinematics/dynamics. According to Newtons third law, if a body exerts a force on a second body, the second body exerts a force on the first body. Both of these forces are equal in magnitude and opposite in direction. This relationship between impulse and momentum demonstrate Newton's third law because the impulse and momentum will always have the same force. Impulse: J= (1000N)(.05s) J= 50 N/s
 * 1. What assumptions did you make in order to complete the calculations in this experiment?**
 * 2. How else could you have calculated the initial velocity?**
 * 3. Why is the Impulse-momentum relationship useful?**
 * 4. Find the magnitude of the impulse delivered to the object.**

The momentum will also be 50 N/s. Use the Formula: m(Vf - Vi) **Mass: 50 kg, Vf:? , Vi:-10 m/s** m(Vf - Vi) 50 (Vf +10) = 50 Vf +10 = 1
 * 5. Determine the change in the object's momentum.**
 * 6. If the object's original velocity was -10m/sec, calculate its final velocity.**
 * Vf = -9 m/s**

The magnitude of the average force would be: __.05*1000 + .10*1000__ = 100 N/s 2
 * 7. What was the magnitude of the "average force" acting on the object during the time graphed?**

i) How would you change the lab to address the errors?** To make sure the box did not turn while the the ball hit it, we could make sure that the ball hits the box directly in the center of the back of the box, by making a target. To make sure the box is placed in the exact same spot every time we could remeasure the distance to double check. It is important to know and understand the the relationship between impulse and and momentum because in real life, every object that is exerting force has an equal and opposite force, for example a baseball and baseball bat.
 * __Evaluation/Conclusion__ - Part 3: Implications for further discussion
 * ii) What is a relevant real-life application of this concept? (Why is this important to know/understand?)**

Errors i) How much?**
 * __Evaluation/Conclusion__- Part 2


 * __Percent Difference:__**

__|measurement-calculation|__ avg *100

__|9.4-8.59|__ 13.29 *100

=6.09%

-When the ball hit the box, the box could have shifted positions, meaning it could have turned throwing off the measurements. -When putting the box back, it might not have been perfectly lined up with the tape, meaning that the measurements could be off slightly time. ** -The error occurred because each time that we put the box back on the tape, we couldn't get it lined up perfectly meaning that the measurements could be slightly off. -While throwing the ball, the tape could have been a little tangled, slowing the throw just a small bit, but not enough to be noticeable. -This wasn't from carelessness, it came from simply misaligning the box, or the tape just slowing the throw down slightly.
 * ii) Where did the error occur?
 * iii) Why did the error occur?**