Lab-7

Group 7 aka //Group Awesome//
**Group Members:** Period: 8th Pat Reynolds Savannah Barkley Tom Tillison George Pamfilis


 * Lab #17: Impulse of a Softball**


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


 * Hypothesis**:The impulse will be equal and opposite.






 * Calculations:**


 * Distance Box Traveled:** .015m
 * Mass of Softball**: .183 kg
 * Mass of Packed Box**: 1.3kg
 * Total Mass of Packed Box and Softball**: 1.438kg
 * Friction Force:** 7.8 N

W-friction= F(f)=7.8(.015)cos(180)= -1.17 J
 * Calculation #1:**

KE 2 ball/box= -W-friction=0 KE 2 ball/box= W f = 1.17 J
 * Calculation #2:**

V2=sqrt(KE/(.5*m)) =(1.17/(.5*1.483))^1/2 = 1.2561 (m/s)
 * Calculation # 3:**

Impulse= m(change in) v =(1.483)(V2-0) =(1.483)(1.2561) Impulse=1.862 (Kg*m/s)
 * Calculation #4:**

Since impulse is equal to momentum and the conservation of momentum states that what you start with is what you must end with, the impulse the ball had on the box is going to be equal to 1.862 (Kg*m/s)
 * Calculation # 5**

mball*vball = (ball mass + box mass)(v2) 0.183v1 = (0.183 + 1.3)(1.256) 0.183V1 = 1.86 V1 = 10.17 (m/s)
 * Calculation # 6:**

__|Actual- Theoretical|__ x100 Theoretical %= |__11.09- 10.17|__ x 100 11.09 % Difference= 8.944%
 * Calcualtion # 7:**

__11.09+10.17__ = 10.634 (m/s) 2
 * 8. Average:Vi of ball from DS + Calculate Vi of ball/2**



__**Discussion Questions:**__

The assumption made made was that since the final velocity was equal to zero the initial must have a substantially larger magnitude. our calculations confirm that the calculated initial velocity and measured by the picket fence photo gate had a percent difference in the range of 2%-9%.
 * __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 (without using energy or momentum conservation)?__**

Another way, maybe more long and vigorous, would be by using the properties of kinematics and dynamics that we learned earlier in the year.


 * __3. Why is the impulse-momentum relationship a useful one?__**

The equation indicates that force times time is equal to the mass times the **__change__** in velocity of the object under our study. In this case we did not have the time nor the force so the only thing we needed was the mass, the final and initial velocity of the object. this how the structure of the equations in excel were based on.


 * __4. Find the magnitude of the impulse delivered to the object.__**



J=F*t J=(1000N)(0.5s) J= 50 N*s

Thanks to the existence of the impulse momentum relationship. And since they are related because impulse=change in momentum that leads to us to infer that the change in momentum would be 50N*s.
 * __5. Determine the change in the object's momentum.__**

m(vf - vi) = impulse. 50 (vf +10) = 50 Vf +10 = 1
 * __6. If the object's original velocity was -10 m/sec, calculate its final velocity.__**
 * Vf = -9 m/s**

__**7. What was the magnitude of the "average force" acting on the object during the time graphed?**__ (0.05)(1000)+(0.10)(1000)/2=100N/s



**__Conclusion__**

//In t//his lab we tested whether or not the //"the impulse will be equal and opposite",// this was our hypothesis. our claim was tested by throwing a ball into a box. By measuring the displacement, the initial velocity of the ball with an electronic photo gate and then performing certain calculations, the percent difference between both of them ranged between 2%-9%. our calculations indicated as show in previous labs that Work is equal and opposite of Kinetic Energy. The conservation of impulse was also observed because when the ball had a certain momentum when it hit the box and displaced it from its original position the momentum of the ball equaled the momentum of the ball and the box together. The way i would use this as also for the car analysts is for car testing and accidents and bullets ignited out of guns. Possible sources of error would be the tape jamming in the photo gate, we encountered that problem a couple of times and had to restart.