PASCO ME-8930 SMART TIMER User Manual

Page 23

012–06734A

Smart Timer

Experiment Three: Conservation of Momentum In Collisions

EQUIPMENT AND MATERIALS REQUIRED

Smart Timer (ME-8930)

(2) Photogate (ME-9498A)

Collision Cart with mass (2) (ME-9454)

(2) Photogate Bracket (Part No. 003-04662)

Dynamics Cart Track (ME-9429A)

(2) Smart Timer Picket Fence

balance

Purpose

The purpose of this experiment is to show that momentum is conserved in collisions.

Theory

When two carts collide with each other, the total momentum ( p = mv ) of both carts is

conserved regardless of the type of collision. An elastic collision is one in which the two

carts bounce off of each other with no loss of kinetic energy — accomplished in this

experiment, through the use of the carts’ magnetic bumpers. A completely inelastic collision

is one in which the two carts hit and stick to each other—accomplished in this experiment

using the Velcro patches on one end of each cart.

Procedure

PART A: Inelastic Collisions

1. Level the track by setting a cart on the track to see which way it rolls. Adjust the

leveling screw at the end of the track to raise or lower that end until a cart placed at rest

on the track will not move.

2. Put a Picket Fence into the slots in the top of each cart and place the Collision Carts so

the Velcro patches face each other. Position the two photogates just far enough apart so

the collision can take place between the photogates. Adjust the height of the photogate

so the 1 cm fence will block the photogate beams. Connect the photogates to the Smart

Timer (see Figure 3.1).

Smart Timer Picket Fence

Figure 3.1

Experiment setup for

Conservation of Momentum experiments

Photogate 2

Photogate 1

to channel 2
of the Smart
Timer

to channel 1
of the Smart
Timer

1 cm flag

Adjustable
End Stop

photogate brackets

leveling
foot

1 cm flag