Purpose, Theory – PASCO ME-6815 PROJECTILE CATCHER ACCESSORY User Manual
Page 15
012-05091E
Projectile Catcher Accessory
11
Exp. 2: Conservation of Momentum
in an Inelastic Collision
EQUIPMENT NEEDED
– Projectile Launcher (ME-6800)
– Projectile Catcher Accessory (ME-6815)
– computer photogate timing system (such as Series 6500, or Science Workshop™)
– timing program*
– (3) Photogates (ME-9498)
– Photogate Bracket for Launcher (ME-6821)
– Dynamics Track (ME-9435A)
– Dynamics Cart (ME-9430)
– Photogate Bracket for Dynamics Track
➤
NOTE: For timing systems with only two photogate capacity, use the PASCO Four-
to-One Adaptor (CI-6820) to accommodate 3 photogates, and use the "Motion
Timer" data collection choice.
*Precision Timer, IDS Timer, Smart Pulley Timer, DataStudio
TM
or Science
Workshop®.
Purpose
The purpose of this experiment is to show that during an inelastic collision, momen-
tum is conserved and energy is not conserved.
Theory
A ball is launched horizontally and embeds in the catcher mounted on the dynamics
cart. The cart and ball then move off at a constant velocity. See Figure 2.1.
CAUTION!
DO NOT LOOK
DOWN BARREL!
CAUTION!
DO NOT LOOK
DOWN BARREL!
CAUTION!
DO NOT LOOK
DOWN THE
BARREL.
LONG
RANGE
MEDIUM
RANGE
SHORT
RANGE
Position
of Ball
Launch
SHORT RANGE
PROJECTILE LAUNCHER
ME-6800
Yellow Band in Window
Indicates Range.
9
0
8
0
7
0
6
0
5
0
4
0
3
0
2
0
1
0
0
WEAR
SAFETY
GLASSES
WHEN IN USE.
Use 25 mm
balls ONLY!
CAUTION!
DO NOT LOOK
DOWN BARREL!
CAUTION!
DO NOT LOOK
DOWN BARREL!
CAUTION!
DO NOT LOOK
DOWN THE
BARREL.
LONG
RANGE
MEDIUM
RANGE
SHORT
RANGE
Position
of Ball
Launch
SHORT RANGE
PROJECTILE LAUNCHER
ME-6800
Yellow Band in Window
Indicates Range.
9
0
8
0
7
0
6
0
5
0
4
0
3
0
2
0
1
0
0
WEAR
SAFETY
GLASSES
WHEN IN USE.
Use 25 mm
balls ONLY!
Before Collision
m
b
v
o
m
c
v = o
m
c
+
m
b
v
After Collision
Figure 2.1: Conservation of Momentum
Momentum is conserved during the collision, but energy is not conserved. The mo-
mentum before the collision is equal to the momentum after the collision:
P
before
= P
after
m
b
v
o
= m
b
+ m
c
v
c