Momentum and Impulse

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Momentum and Impulse

• Chapter 6, Section 1
• Pg. 208 - 214

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6.1- Momentum and Impulse
Momentum is a measure on how difficult it is to
stop a moving object.
Momentum is a vector quantity.
p m?
Measured in kg m/s
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Objects with a high momentum can have a greater
mass, velocity, or both!
?1 ?2 m1 gt m2
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Falling Object 1
Falling Object 2
?1 gt ?2 m1 m2
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A change in momentum takes force and time.
SF?t ?p
This product of force and the time over which it
acts on an object is known as an impulse (F?t).
SF?t mvf mvi Impulse-Momentum Theorem
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Wall exerts an impulse on the moving ball,
thereby causing a change in momentum
p1
p2
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Sample Problem
A 1400 kg car moving westward with a velocity of
15 m/s collides with a pole and is brought to
rest in 0.30 s. What is the magnitude of the
force exerted on the car during the collision?
(Pg. 211)
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SF?t m?f m?i
SF (0.30 s) (1400 kg)(0 m/s) (1400 kg)(- 15
m/s)
SF (0.30 s) 21,000 kg m/s
SF 7.0 x 104 N to the East
m 1400 kg ?i -15 m/s
?t 0.30 s ?f 0 m/s