Lab Inelastic Collisions - Velocity of a Softball

A Ballistic Pendulum Analog

 Enter each group member's AIDE letters Lab Station # Choose One 1 2 3 4 5 6 7 8 9 10 11 12 13 Period Choose One 1 2 3 4 5 6 7 8

Equipment: cardboard box, packing material (plastic bags and paper), softball, meterstick, spring scale, triple beam balance

Purpose: To determine the velocity of a softball using equations from the law of conservation of momentum and work-energy relationships.

Procedure and Data:

1. Loosely pack a cardboard box with packing material so that a softball thrown into the box will remain trapped - you do not want the ball to "bounce back out!"

2. Measure and record the mass of the softball and then the mass of the packed box.

 mass of softball not selected grams kilograms mass of packed box not selected grams kilograms total mass of packed box and softball not selected grams kilograms

3. Place the box on a smooth surface and mark its starting position.

4. Throw (do not roll) the softball into the box - be careful to not tip the box over or cause it to spin, you only need to throw the ball fast enough to move the box 3-8 centimeters in a straight line.

5. Measure and record the distance the box moved.

distance box travelled

6. Measure the force of friction by pulling the box (with the ball still trapped inside) at a constant speed across the same section of floor. Remember that the spring scale MUST remain parallel to the floor.

frictional force

Calculations and Analysis.

1. How much work was done on the box by friction as the box, packing and softball slid to a stop after the collision?

frictional work formula

calculations

numerical frictional work

Enter your data for friction and distance traveled in the EXCEL spreadsheet, impulse.xls to verify your calculations.  Then complete the following statement:  The work done by a force F acting through a distance s is determined graphically as the of the graph.

 acceleration not selected joules kilograms meters meters/sec meters/secē newtons .

Which forces would belong on a freebody diagram of the box
as it slides to a stop? (assume that it is moving towards the right)
 1 2 3 4 5 6

2. How fast was the box, packing and softball moving immediately following the collision? Show your equations and calculations as well as your final numerical solution.

formula to discover the velocity of the box, paper and ball immediately following the collision

 calculations you can make a ē by pressing the keys Alt 0178

numerical velocity of box, paper and ball immediately following the collision

3. What impulse did the softball deliver to the box and packing material? Show your equations and calculations as well as your final numerical solution.

formula to discover the impulse delivered to the box and packing
material by the ball's impact

 calculations

numerical impulse delivered to the box and packing material
by the ball's impact

4. By Newton's third law, the impulse delivered to the box and packing material equals the impulse received by the ball.  Using this information, calculate the initial velocity of the softball.

 calculations

initial velocity of the ball just before its impact with the box
and packing material

5. Devise a follow-up experiment that could be conducted to verify the value for the velocity calculated in question #4.