Product: Inquiry Lab Template
Modified Ballistics Pendulum.
Grade Level/Subject / Physics (all levels but probably best for higher level courses)Unit / momentum
Enduring Understanding / Impulses cause changes in momentum, and momentum is conserved during collisions.
SOL Objectives / PH.6.b The student will investigate and understand that quantities including mass, energy, momentum, and charge are conserved. Key concepts include elastic and inelastic collisions.
Title / Modified Ballistics Pendulum
Lesson Objective / Students analyze an inelastic collision using momentum to determine the landing position of a launched object
Inquiry Level / 3
Materials Required / Ramp setup
(google marble projectile and collision ramp)
Carbon paper
Scale
Note: energy cannot be used to determine speed of ball that rolls down the ramp unless rotational energy is considered.
Note: Balancing the wooden "catch" bead can be tricky. Consider using a very small bit of modeling clay to hold it in place.
Note: Kids are amazed by carbon paper.
Note: A great review of kinematics and projectiles
Modified Ballistics pendulum lab
Intro:
A ballistic pendulum is often used to measure the initial speed of bullets. A bullet is shot into a block of wood attached to a pendulum. The bullet lodges in the wood and the two swing as a unit as a pendulum. The final height reached by these two objects allows for the calculation of bullet's initial speed.
In this experiment, you will use a similar setup to determine where to place a cup in order to catch the marble. Extra points are awarded for hitting it on the first try.
Equipment:
The equipment is at each table. Instead of shooting a bullet, you will roll a metal ball down a ramp. This allows the velocity of the ball to be a constant. At the bottom of the box, the marble will be caught by a wooden “ball”. Together the two will fly through the air and hit the floor. Placing a piece of carbon paper on the floor, over a piece of paper, allows you to exactly determine where the balls hit.
- Using your knowledge of energy, momentum, and kinematics, determine the initial velocity of the ball at the bottom of the ramp. Then, determine where to place the target cup.
- Determine how much, if any, energy is lost during the collision. If energy is lost, explain where it goes.