Lab-8

**Lab: Impulse of a Ball**

 * Abby Strauss, Gianna Cortazzo, Brianna Formicola, Jacqui Abend**
 * Period 8**
 * Completed: 2/9/10 Due: 2/10/10**


 * Objective**: The impulse of the softball on the box and the impulse of the box on the softball will be equal.


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

mass of ball: 0.184 kg mass of box: 1.400 kg mass of ball/box system: 1.584 kg
 * Data**:


 * Sample Calculations:**

1.) Work Done by Friction Bringing the Box To a Stop: Wfriction = f * d Wfriction = 5.5 * 0.095 Wfriction = .523 J

2.) Kinetic Energy of the Box/Ball System: KEball/box - Wfriction = 0 KEball/box = Wfriction = .523 J

3.) The Initial Velocity (v2) of the Box/Ball System: KE2 = ½ mv2 .523 = ½ (1.584)v2 v2 = .66 v = .81 m/s

4.) Momentum of the Box-Ball System: & 5.) Impulse That the Softball Delivered to the Box and Packing Material: Impulse = m * delta v Impulse = (.1583) (-.81) Impulse = -1.28 kg m/s

6.) Initial Velocity of the Softball: Impulse on Ball + 1.28 kg m/s

7.) Velocity of the Ball Measured by the Motion Sensor: Impulse= m* delta v __1.28__ = __.184 vi__ .184 .184 vi= 6.96 m/s

% Difference: measurement-calculation/ average (measurement +calculation) x 100 6.63-6.96 / 6.795 x 100 % difference= 4.85 %


 * Graph**:
 * Discussion** **Questions:

1. What assumptions did you make in order to complete the calculations in this experiment? **
 * We made the assumption that the final velocity was 0.**

2. How else could you have calculated the initial velocity (without using energy or momentum conservation?
 * We could have used kinematics and dynamics to solve for the acceleration, and then use that to find the initial velocity.**

3. Why is the impulse-momentum relationship a useful one?
 * The impulse-momentum relationship is a useful one because it shows Newton's Third Law. Newton's Third Law states that there is a direct relationship between impulse and momentum so impulse and momentum will be the same.**

4. Find the magnitude of the impulse delivered to the object. J=(1000N)(0.5s) J= 50 N/s**
 * J=F*t

5. Determine the change in the object's momentum.
 * Momentum is equal to impulse, therefore the object's momentum is also 50 N/s.**

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

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


 * Conclusio****n:**
 * The purpose of this lab was satisfied because we were able to compare the impulse of a softball on a box to the impulse of the box on a softball. Our hypothesis was proven correct, that the impulse of a softball on a box and the impulse of the box on a softball are equal because there is a direct relationship between impulse and momentum making them equal. As we completed this lab we found that when the velocity of the ball was increased the force of the ball on the box was increased with it making the box slide a distance. ** Our lab generated a percent difference of %4.58. Causes for error were worn out springs when measuring friction, and the spinning or shifting of the box when the ball was thrown. In order to address the errors in the lab I would make sure the spring we used was new so none of the springs uncoiled and it was not worn out.