linear momentum physics mrs. coyle. linear momentum, p p= m v momentum is a vector. the direction of...
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Question 1: What has more momentum, a dump truck at rest or a pebble moving down a hill at 1m/s?TRANSCRIPT
Linear Momentum
PhysicsMrs. Coyle
Linear Momentum, p
p= m v • Momentum is a vector.• The direction of momentum is the same as the
direction of the velocity of the object.• Unit: kg m/s or N s• “Inertia in Motion”
Question 1:
• What has more momentum, a dump truck at rest or a pebble moving down a hill at 1m/s?
Question 2
• How can you change the momentum of an object?
Impulse =
Impulse = p = m v = Ft
Problem 1
• Starting with Newton’s second law, show that for a constant force, p = m v = Ft .
To reduce the force of impact, increase the time of impact.
For a given change in velocity, p is constant :
Question 3:
• How do you have a better chance of winning in a water balloon toss contest?
Question 4:
• Why does a boxer “roll with the punches”?
Question 5:
• Why should you follow through in a serve when playing tennis, or when hitting a baseball?
Problem 2A ball at rest has a mass 0.5kg andis kicked with a force of 40N. Theimpact lasts 0.2s. Find:a)The change in momentum of the ball.b)The final velocity of the ball.
Answer: a) 8 Ns, b)16m/s
Problem 3
• A football player of mass 130kg travelling at 12.0m/s collides with another player and comes to rest in 0.90s. What was the force of impact?
• Answer:1,733N
Impulse is the area under the curve in a graph of F vs t.
F
t
Some Engineering Applications
Question 6
• Why are airbags used?
M
A
R
S
E
XPLORATION
MARS LANDER AIR BAGS
Rover Exits the Lander
Applications in Engineering Household Items
MILK BOTTLES
THE EGG CARTON