Warm up. Physics Honors AB –Day 1/12/15-1/13/15 Momentum and Impulse.
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Warm up •A 3.00 kg crate slides down a ramp. The ramp is 1.00 m in length and inclined at an angle of 30. The crate starts from rest at the top, and the ramp is essentially frictionless, and continues to move a short distance on the horizontal floor after it leaves the ramp. •Use energy methods to determine the speed of the crate at the bottom of the ramp. •How far does it slide on the floor after it leaves the incline if it experiences a 5 N frictional force will sliding on the floor.
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Transcript of Warm up. Physics Honors AB –Day 1/12/15-1/13/15 Momentum and Impulse.
Warm up• A 3.00 kg crate slides down a ramp. The
ramp is 1.00 m in length and inclined at an angle of 30. The crate starts from rest at the top, and the ramp is essentially frictionless, and continues to move a short distance on the horizontal floor after it leaves the ramp. • Use energy methods to determine the speed
of the crate at the bottom of the ramp.• How far does it slide on the floor after it
leaves the incline if it experiences a 5 N frictional force will sliding on the floor.
Physics HonorsAB –Day
1/12/15-1/13/15Momentum and Impulse
Agenda
• Review• Conservation of Momentum • Conservation of Energy • Collisions – Elastic and Inelastic
Potential Energy• Stored energy
Kinetic Energy•Energy due to an object in motion
Dependent on Velocity
Mechanical Energy• The sum of kinetic and all forms of Potential Energy
Mechanical Energy is often conserved; in absence of friction
Momentum• Describes object motion• “How easy it is to stop an object in motion”
Linear momentumVectorUnits -
Impulse• Equations
Impulse – Momentum Theorem
Conservation of MomentumMomentum is conserved in collisions and for objects pushing away from each other
These equations come directly out of Newton’s Third law
Conservation of MomentumA 63 kg astronaut is in space and throws a 10 kg oxygen tank towards Earth with a speed of 12.0 m/s. Assuming the astronaut starts from rest, find the final velocity of the astronaut after the throw.
Conservation of Momentum in Space• Linear Momentum in Space
Collisions• Elastic Collisions are collisions in which both
momentum and kinetic energy are conserved• Bounce off
• Inelastic Collisions are when momentum is conserved but not Kinetic Energy; total energy conserved still• Special Case: When they stick together
Elastic Collision• A 16 kg canoe moving to the left at 12 m/s makes an elastic head-
on-collision with a 4.0 kg raft moving to the right at 6.0 m/s. After the collision, the raft moves to the left at 22.7 m/s. Disregard any water effects.• Find the velocity of the second ball after the collision.
Inelastic Collisions
A 1500 kg traveling at 15 m/s to the south collides with a 4500 kg truck that is initially at rest. The car and truck stick together and move together after the collisions. What is the final velocity of the two vehicle mass?
