physics
Download
Skip this Video
Download Presentation
Physics

Loading in 2 Seconds...

play fullscreen
1 / 29

Physics - PowerPoint PPT Presentation


  • 87 Views
  • Uploaded on

Physics. Chapter 9 Momentum and its Conservation. Momentum and its Conservation. Let’s check our knowledge (1-12). Define momentum. Momentum The quantity of motion The property of an object in motion. What two things must an object have to have momentum?. Mass (kg) Velocity (m/s).

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about ' Physics' - shaeleigh-harper


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
physics

Physics

Chapter 9

Momentum and its Conservation

momentum and its conservation
Momentum and its Conservation
  • Let’s check our knowledge (1-12)
define momentum
Define momentum.

Momentum

  • The quantity of motion
  • The property of an object in motion
explain how inertia is different than momentum
Explain how inertia is different than momentum.
  • Inertia is a property of any object with mass
  • It is the tendency of an object to resist a change in its velocity
  • Momentum is a property of an object in motion
  • A stationary object has no (O) momentum
  • An object must be moving to have momentum but not inertia
how do you calculate momentum
How do you calculate momentum?
  • Multiple mass by velocity
  • Momentum = mv
what is the symbol and unit for momentum
What is the symbol and unit for momentum?
  • p (actually rho-)
  • kgm/s
define impulse
Define impulse.
  • Force applied to an object over a time interval to change its momentum
explain how impulse is different than momentum
Explain how impulse is different than momentum.
  • Momentum is the property of an object in motion.
  • Impulse is force applied for a certain time that causes an object’s momentum to change.
how do you calculate impulse
How do you calculate impulse?
  • Multiply force applied by time of application
  • Impulse = Ft
what is the unit for impulse
What is the unit for impulse?
  • N•s
  • There is no symbol for impulse!
are momentum and impulse vector quantities
Are momentum and impulse vector quantities?
  • Yes
  • They both have magnitude (size) and direction
slide14
Use Newton’s Second law of Motion and the definition of acceleration to derive the relationship between impulse and change in momentum.
  • F = ma and a = v/t
  • F = mv/t
  • Ft = mv (fat mav)
write down the impulse momentum theorem explain it in words
Write down the Impulse- Momentum Theorem. Explain it in words.
  • Ft = p2 – p1
  • FΔt = mΔv
  • Impulse (Ft) on an object causes its initial momentum (p1) to change to its final momentum (p2).
if a tennis ball is hit by a racket for 0 15 s with a force of 23 n find its
If a tennis ball is hit by a racket for 0.15 s with a force of 23 N find its:
  • Beginning momentum
  • Impulse given it by the racket
  • Change in momentum
  • Final momentum
if a tennis ball is hit by a racket for 0 15 s with a force of 23 n find its1
If a tennis ball is hit by a racket for 0.15 s with a force of 23 N find its:
  • Beginning momentum: 0 kg*m/s
  • Impulse given it by the racket: 3.45 N*s
  • Change in momentum: 3.45 kg*m/s
  • Final momentum: 3.45 kg*m/s
explain using the terms momentum and impulse why automobile airbags save lives
Explain using the terms momentum and impulse why automobile airbags save lives.
  • When a person stops there is the same change in momentum with or without the airbag.
  • The airbag increases the time for the force so it is less (Ft = mv)
a 725 kg compact car is moving at 100 km h towards the east find its momentum kg m s
A 725 kg compact car is moving at 100 km/h towards the east. Find its momentum (kg*m/s)
  • 100 km/h = 27.8 m/s (?)
  • p = mv = (725)(27.8) = 20155 kg*m/s
slide20
If the driver of the 725 kg car traveling at 27.8 m/s, applies the brakes for 2 s and the brakes apply an average force of 5000N. Find:
  • The impulse given to the car
  • The car’s change in momentum
  • The car’s final momentum
  • The car’s final velocity
slide21
If the driver of the 725 kg car traveling at 27.8 m/s, applies the brakes for 2 s and the brakes apply an average force of 5000N. Find:
  • The impulse given to the car: - 10,000 N*s
  • The car’s change in momentum: - 10,000 kg*m/s
  • The car’s final momentum: 10,155 kg*m/s
  • The car’s final velocity: 14 m/s
state newton s third law of motion
State Newton’s Third Law of Motion
  • For every action there is an equal and opposite reaction
state the law of conservation of momentum
State the Law of Conservation of Momentum
  • The momentum of any closed, isolated system doesn\'t change
  • In a closed, isolated system, the initial momentum is equal to the final momentum
what is a closed system
What is a closed system?
  • A system where mass is not lost or gained.
what is the difference between internal forces and external forces on a system
What is the difference between internal forces and external forces on a system?
  • Internal forces are those forces that act within the system.
  • External force are forces acting on the system from the outside (the surroundings)
what is an isolated system
What is an isolated system?
  • When no external forces act upon the system.
how is an isolated system different from a closed system
How is an isolated system different from a closed system?
  • A closed system can have an outside force acting upon it but an isolated system cannot.
slide28
For the Law of Conservation of Momentum to be true, must a system be closed or isolated or both. Explain.
  • An isolated system is also closed, so it must be isolated (and thus also closed).
  • If only closed momentum can still be transferred to it by way of an outside force
slide29
If there is no air in outer space for a rocket to push off of, explain how when a rocket fires its engines in space it can move.
  • The escaping gas pushes off the rocket and the rocket pushes off the gas with the same force.
  • This causes and equal and opposite change in momentum for both
  • So both move but in opposite directions (and speeds)
ad