chapter 6 - momentum and collisions
DESCRIPTION
Chapter 6 - Momentum and Collisions. 6.1 - Momentum and Impulse. Review. Energy cannot be created or destroyed, but only changed from one form to another Newton’s 3 laws Kinetic energy is the energy of motion: KE=1/2 mv 2. Momentum and Impulse. - PowerPoint PPT PresentationTRANSCRIPT
![Page 1: Chapter 6 - Momentum and Collisions](https://reader035.vdocuments.net/reader035/viewer/2022081418/568139d9550346895da18da7/html5/thumbnails/1.jpg)
Chapter 6 - Momentum and Collisions6.1 - Momentum and Impulse
![Page 2: Chapter 6 - Momentum and Collisions](https://reader035.vdocuments.net/reader035/viewer/2022081418/568139d9550346895da18da7/html5/thumbnails/2.jpg)
ReviewEnergy cannot be created or
destroyed, but only changed from one form to another
Newton’s 3 lawsKinetic energy is the energy of
motion: KE=1/2 mv2
![Page 3: Chapter 6 - Momentum and Collisions](https://reader035.vdocuments.net/reader035/viewer/2022081418/568139d9550346895da18da7/html5/thumbnails/3.jpg)
Momentum and ImpulseMomentum is a vector quantity
defined as the product of an object’s mass and velocity
SI units are kilogram-meters per second
p =mv
kg ⋅m/s
![Page 4: Chapter 6 - Momentum and Collisions](https://reader035.vdocuments.net/reader035/viewer/2022081418/568139d9550346895da18da7/html5/thumbnails/4.jpg)
Momentum and ImpulseA change in momentum takes force
and time
Impulse-Momentum TheoremFΔt=Δp
or
FΔt=Δp=mvf −mvi
![Page 5: Chapter 6 - Momentum and Collisions](https://reader035.vdocuments.net/reader035/viewer/2022081418/568139d9550346895da18da7/html5/thumbnails/5.jpg)
Momentum and ImpulseExplains why follow-through is
important in many sportsImpulse is the product of the force
and the time over which it acts on an object
Determines stopping times and distances
![Page 6: Chapter 6 - Momentum and Collisions](https://reader035.vdocuments.net/reader035/viewer/2022081418/568139d9550346895da18da7/html5/thumbnails/6.jpg)
Momentum and ImpulseA change in momentum over a longer
time requires less forceExample
The egg fall
![Page 7: Chapter 6 - Momentum and Collisions](https://reader035.vdocuments.net/reader035/viewer/2022081418/568139d9550346895da18da7/html5/thumbnails/7.jpg)
HW AssignmentPage 209: Practice 6APage 211: Practice 6BPage 213: Practice 6C
![Page 8: Chapter 6 - Momentum and Collisions](https://reader035.vdocuments.net/reader035/viewer/2022081418/568139d9550346895da18da7/html5/thumbnails/8.jpg)
Chapter 6 - Momentum and Collisions6.2 - Conservation of momentum
![Page 9: Chapter 6 - Momentum and Collisions](https://reader035.vdocuments.net/reader035/viewer/2022081418/568139d9550346895da18da7/html5/thumbnails/9.jpg)
Conservation of momentumWe have looked at the momentum of
one objectIf two or more objects are interacting
with each other then the total momentum of all objects remains constant regardless of the nature of the forces between the objects
![Page 10: Chapter 6 - Momentum and Collisions](https://reader035.vdocuments.net/reader035/viewer/2022081418/568139d9550346895da18da7/html5/thumbnails/10.jpg)
Conservation of momentumMomentum is conserved in collisions
Momentum is also conserved for objects pushing away from each other
m1v1, i +m2v2, i =m1v1, f +m2v2, f
total initial momentum = total final momentum
![Page 11: Chapter 6 - Momentum and Collisions](https://reader035.vdocuments.net/reader035/viewer/2022081418/568139d9550346895da18da7/html5/thumbnails/11.jpg)
Chapter 6 - Momentum and Impulse6.3 - Elastic and inelastic collisions
![Page 12: Chapter 6 - Momentum and Collisions](https://reader035.vdocuments.net/reader035/viewer/2022081418/568139d9550346895da18da7/html5/thumbnails/12.jpg)
Perfectly inelastic collisionsA collision in which two objects stick
together and move with a common velocity after colliding
After the collision, the two objects become essentially one object
![Page 13: Chapter 6 - Momentum and Collisions](https://reader035.vdocuments.net/reader035/viewer/2022081418/568139d9550346895da18da7/html5/thumbnails/13.jpg)
Perfectly Inelastic CollisionsIn this case, we get a simplified
version of the equation for conservation of momentum
using this equation, pay attention to the signs indicating direction
What happens in terms of Kinetic Energy?
m1v1, i +m2v2, i =(m1 +m2)vf
![Page 14: Chapter 6 - Momentum and Collisions](https://reader035.vdocuments.net/reader035/viewer/2022081418/568139d9550346895da18da7/html5/thumbnails/14.jpg)
Perfectly Inelastic CollisionsConsider the following Situation:m1 = 1kg v1 = 5 m/sm2 = 2kg v2 = 3 m/s
![Page 15: Chapter 6 - Momentum and Collisions](https://reader035.vdocuments.net/reader035/viewer/2022081418/568139d9550346895da18da7/html5/thumbnails/15.jpg)
Conservation of MomentumVideo Demonstration
![Page 16: Chapter 6 - Momentum and Collisions](https://reader035.vdocuments.net/reader035/viewer/2022081418/568139d9550346895da18da7/html5/thumbnails/16.jpg)
Practice ProblemA clay ball with a mass of 0.35 kg hits
another 0.35 kg ball at rest, and the two stick together. The first ball has an initial speed of 4.2 m/s.
• What is the final speed of the balls?• Calculate the decrease in kinetic
energy that occurs during the collision
• What percentage of the kinetic energy is converted to other forms of energy?
![Page 17: Chapter 6 - Momentum and Collisions](https://reader035.vdocuments.net/reader035/viewer/2022081418/568139d9550346895da18da7/html5/thumbnails/17.jpg)
Elastic CollisionWhen two objects collide and return to
their original shapes with no change in momentum and no change in total kinetic energy
m1v1, i +m2v2, i =m1v1, f +m2v2, f
1
2m1v1, i2 +
12m2v2, i2 =
12m1v1, f2 +
12m2v2, f2
![Page 18: Chapter 6 - Momentum and Collisions](https://reader035.vdocuments.net/reader035/viewer/2022081418/568139d9550346895da18da7/html5/thumbnails/18.jpg)
CollisionsMost collisions are neither elastic nor
perfectly inelasticEven in nearly elastic collisions, there
is some deformation and loss of kinetic energy as a result
In most collisions, some kinetic energy is converted into sound
![Page 19: Chapter 6 - Momentum and Collisions](https://reader035.vdocuments.net/reader035/viewer/2022081418/568139d9550346895da18da7/html5/thumbnails/19.jpg)
HW AssignmentPage 224, Practice 6E: 1, 3, 5Page 226, Practice 6FPage 229, Practice 6G: 1, 3, 4