1. Whiteboard Protocol
Bell Work: What is the KE of a man that has a mass of 25 kg and moving at 10 m/s?
Objective: TLW how to calculate momentum.
Classwork: Physics book page 199; practice A
Exit Slip: What is the momentum of a toy that has a mass of 5 kg moving at 5 m/s?
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2. Concept Summary High School Physics
Impulse & Momentum
Concept Summary
High School Physics
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3. Momentum
Momentum is what Newton called the “quantity of motion” of an object.
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4. Momentum The momentum of an object: Depends on the object’s mass.
Momentum is directly proportional to mass.
Depends on the object’s velocity.
Momentum is directly proportional to velocity.
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5. Momentum
In symbols:
p = mv p m v
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6. Momentum Momentum is a vector quantity.
Common units of momentum: kg m/s
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7. Impulse The impulse exerted on an object depends on:
The force acting on the object.
Impulse is directly proportional to force.
The time that the force acts.
Impulse is directly proportional to time.
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8. Impulse
In symbols:
I = Ft I F t
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9. Impulse Impulse is a vector quantity. Common units of impulse: N s
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10. Impulse & Momentum
The impulse exerted on an object equals the object’s change in momentum.
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11. Impulse & Momentum In symbols: I = Dp 5/24/2019

12. Conservation of Momentum
Since impulse = change in momentum, If no impulse is exerted on an object, the momentum of the object will not change.
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13. Conservation of Momentum
If no external forces act on a system, the total momentum of the system will not change.
Such a system is called an “isolated system”.
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14. Conservation of Momentum
Momentum is conserved in every isolated system.
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15. Conservation of Momentum
Another way to think about it is:
Internal forces can never change the total momentum of a system.
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16. Conservation of Momentum
In practice, for any event in an isolated system:
Momentumafter = Momentumbefore
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17. The End.
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