Pasco Scientific ME-9429A, Инструкция по эксплуатации и руководство по экспериментам

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7
012-05035E Dynamics Cart Accessory Track Set
Experiment 1: Conservation of Momentum in Explosions
EQUIPMENT NEEDED:
– Dynamic Cart with Mass (ME-9430)
– Collision Cart (ME-9454)
– Dynamics Cart Track
– Meter stick
– Mass balance
Purpose
The purpose of this experiment is to demonstrate conservation of momentum for two carts
pushing away from each other.
Theory
When two carts push away from each other and no net force exists, the total momentum of
both carts is conserved. Because the system is initially at rest, the final momentum of the
two carts must be equal in magnitude and opposite in direction so the resulting total mo-
mentum of the system is still zero.
p = m
1
v
1
– m
2
v
2
= 0
Therefore, the ratio of the final speeds of the carts is equal to the ratio of the masses of the
carts.
v
1
v
2
=
m
2
m
2
To simplify this experiment, the starting point for the carts at rest is chosen so that the two
carts will reach the end of the track simultaneously. The speed, which is the distance
divided by the time, can be determined by measuring the distance traveled since the time
traveled by each cart is the same.
v
1
v
2
=
Δ
x
1
Δ
t
Δ
x
2
Δ
t
=
Δ
x
1
Δ
x
2
Thus the ratio of the distances is equal to the ratio of the masses:
Δ
x
1
Δ
x
2
=
m
2
m
1
Procedure
➀
Level the track by setting a cart on the track to see which way it rolls. Adjust the leveling
feet to raise or lower the ends until a cart placed at rest on the track will not move.
Leveling foot