1405 Name ______
MOMENTUM
INTRODUCTION
The momentum p of a physical body is defined as the product of its mass and its velocity.
Momentum = mass x velocity
p = mv
It is a vector quantity and every moving physical body has momentum.
When two bodies in motion collide on a near frictionless surface, there is conservation of momentum, that is, the initial momentum of the system is equal to its final momentum. In studying collisions in one dimension you will use the concept of momentum and its conservation. In this experiment you will analyze only elastic and inelastic collisions in one dimension. We will compare the momentum before and after collision.
APPARATUS
In this experiment you will use an air track, several gliders, two of them with equal masses and two Accessory Photogates.
PROCEDURE:ELASTIC COLLISIONS
Equal Masses, One Glider at Rest
1. In this experiment you will level the air track and select two gliders of equal
mass (ma = mb). After you are convinced that the air track is perfectly level (the gliders do
not accelerate in either direction) place two Accessory Photogates, about 40 cm apart.
2. Turn on the computer. Ask your instructor or the lab assistant to help you find the correct file to use to collect your data from the two photogates.
3.Measure the flag’s width and enter it in the computer in meters as instructed.
4.Turn on the air supply to your air track and place both gliders ma and mb as indicated in the figure. Start the timer (click Start on the computer). Keep glider mb at rest on the track and slightly push ma allowing it to glide freely on the track with a constant velocity. After passing through photogate I, the glider ma will collide with glider mb previously at rest. After the collision, glider ma will stop and glider mb will pass through photogate II.
5.Repeat the above steps 2 more times.
Data 1:
Mass of glider a ma = kg
Mass of glider b mb = kg
Va = m direction
s (left or right)
Vb = m direction
s (left or right)
Momentum
Initial: Pi = maVa = kg-m direction
s (left or right)
Final: Pf = mbVb = kg-m direction
s (left or right)
Data 2:
Mass of glider a ma = kg
Mass of glider b mb = kg
Va = m direction
s (left or right)
Vb = m direction
s (left or right)
Momentum
Initial: Pi = maVa = kg-m direction
s (left or right)
Final: Pf = mbVb = kg-m direction
s (left or right)
Data 3:
Mass of glider a ma = kg
Mass of glider b mb = kg
Va = m direction
s (left or right)
Vb = m direction
s (left or right)
Momentum
Initial: Pi = maVa = kg-m direction
s (left or right)
Final: Pf = mbVb = kg-m direction
s (left or right)
According to your results, was momentum conserved?
PROCEDURE: INELASTIC COLLISIONS
Equal Masses, One Glider at Rest
1. Use the same set-up as the Elastic Collision in terms of the level track, starting positions of carts and the photogates. The carts should be revised to attach the inelastic coupling devices to them. Then measure their masses again before starting to take data.
2. Turn on the air supply to your air track and place both gliders ma and mb as indicated in the figure. Start the timer (click Start on the computer). Keep glider mb at rest on the track and slightly push ma allowing it to glide freely on the track with a constant velocity. After passing through photogate I, the glider ma will collide with glider mb previously at rest. After the collision, the gliders will stick together and will pass through photogate II.
3.Repeat the above steps 2 more times.
Data 1:
Mass of glider a ma = kg
Mass of glider b mb = kg
Va = m direction
s (left or right)
Vb = m direction
s (left or right)
Momentum
Initial: Pi = maVa = kg-m direction
s (left or right)
Final: Pf = (ma+ mb)Vb = kg-m direction
s (left or right)
Data 2:
Mass of glider a ma = kg
Mass of glider b mb = kg
Va = m direction
s (left or right)
Vb = m direction
s (left or right)
Momentum
Initial: Pi = maVa = kg-m direction
s (left or right)
Final: Pf = (ma+ mb)Vb = kg-m direction
s (left or right)
Data 3:
Mass of glider a ma = kg
Mass of glider b mb = kg
Va = m direction
s (left or right)
Vb = m direction
s (left or right)
Momentum
Initial: Pi = maVa = kg-m direction
s (left or right)
Final: Pf = (ma+ mb)Vb = kg-m direction
s (left or right)
According to your results, was momentum conserved?
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