Law of Conservation of Momentum
Active Physics
Name: ______________________________Grade:___ Class Period: ___ Date:____________
Essential Question: What is the relationship between the mass and the velocity of an object, in
reference to momentum? PSc.1.1.2
Instructions: Study pp. 63-66 and answer the following questions.
Momentum is equal to mass times velocity. It is symbolized with a small p. Mass is
symbolized with a small m, velocity with a small v.
Momentum(p) equals mass(m) times velocity (v) or p = mv.
1. What is “Conservation of Momentum”? ( p.63)
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2. If the momentum before collision is 500 kg/m/s, then the momentum after the collision is
___________ kg m/s. How does this explain the Law of Conservation of Momentum?
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3. How can a game of billiard be an example of the Law of Conservation of Momentum? ( p. 64)
Think!___________________________________________________________________________
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4. What does the negative sign show or indicate in the Law of Conservation of Momentum? ( p.64)
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5. What is the equation/formula for Newton’s Second Law?
6. What is the equation/formula for acceleration ( a )?
7. What does the symbol
mean in the equation on page 64?
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8. Why is solving conservation of momentum problems easy? ( p. 64-65) Think!
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9. Imagination: Identify and illustrate or draw the different types of collisions. ( p. 65)
Example:
Collision Type 1:
One moving object hits a stationary object and both stick together and move off at the same speed.
before collision
After collision
Collision Type 2:
Collision Type 3:
Collision Type 4:
Collision Type 5:
10. Sample Problem I ( p. 65): Answer the following questions about the problem.
A 75.00 kg ice skater is moving to the east at 3.00m/s toward his 50.00 kg partner, who is moving
toward him( west) at 1.80 m/s. If he catches her up and they move away together, what is their final
velocity?
a. What is the mass and velocity of the skater moving to the east? ( boy)
Mass ( m)=_______________
Velocity ( v)=______________
b. What is the mass and velocity of the skater moving to the west? ( girl)
Mass ( m)=_______________
Velocity ( v)=______________
c. Which direction will you designate as positive( +), east or west? Can you interchange them?
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d. Why is velocity a vector quantity? Review and Think!
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e. What are the given in the problem? ( p. 65)
Mb ( mass of boy) = _______________________________
Mg ( mass of girl) = _______________________________
vb ( velocity of boy) =_______________________________
vg (velocity of girl) = _______________________________
11. Copy and study: Show the solution for the problem. ( p. 66)
12. What is their final velocity? How is momentum conserved?
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Answer: The total momentum of the boy and girl skater is 135 kg m/s 225 kg m/s- 90.0 kg m/s) and
their final momentum is also 135 kg m/s ( 125 kg X 1.08 m/s)
Here is an example calculation. Notice that the unit for momentum is kg-m/s.
Line 1: Definition of momentum.
Line 2: Enter example values for mass and velocity.
Line 3: Calculate the resultant momentum.
Thus, an object with a mass of 3.0 kg that is traveling at a velocity of 4.0 m/s has a
momentum of 12 kg-m/s.
http://zonalandeducation.com/mstm/physics/mechanics/momentum/introductoryProblems/m
omentumSummary1.html