A Ballistic Pendulum Analog
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
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.
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.
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
forces would belong on a freebody diagram of the box
as it slides to a stop? (assume that it is moving towards the right)
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
you can make a ē by
pressing the keys
3. What impulse did the softball deliver to the box
and packing material? Show your equations and calculations as well as your final numerical
formula to discover the 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.
5. Devise a follow-up experiment that could be
conducted to verify the value for the velocity calculated in question #4.