Work Energy And Momentum Flashcards
How do we calculate work?
Work = force x distance moved in direction of force
What do we mean by work done?
The energy transferred when can object is moved.
What is kinetic energy?
The energy it has due to motion.
How do we calculate kinetic energy?
Kinetic energy = 1/2 x mass x speed^2
What type of energy is gravitational potential energy?
Stored energy.
What is Elastic potential energy
The energy stored in an elastic object when work is done to the object.
How can we tell if an object is elastic?
It returns to its shape after being squashed or stretched.
What is momentum?
A property all moving objects possess.
How do we calculate momentum?
Momentum = mass x velocity.
The most important property of momentum is….
Momentum is conserved whenever two objects interact provided no forces act on them.
What is changing momentum called?
Impact force.
How do we calculate impact force?
Force = change in momentum / time taken
How do we lessen the impact force?
Increase the time for an objects momentum to reach 0.
What do air bags do?
Increase the time taken for your head’s momentum to reach 0.
Work done to overcome friction is transferred into what?
Mainly heat energy but some sound energy too.
How do we calculate GPE?
GPE = mass x gravitational field strength x change in height.
When an object moves up does It lose GPE?
No, it gains GPE.
When an object falls what is GPE transferred to?
Kinetic energy.
Objects prefer to keep moving in the same direction what does this make it difficult to do to objects?
Change the direction of an object with a lot of momentum
When two objects push each other apart….
They move apart with equal and opposite momentum.
When does a change in momentum occur?
When a force is applaud to the object.
Give two ways in which momentum can change?
If the object speeds up or slows down.
Changes direction.
The longer the time taken for the change in momentum, the…
Smaller the impact force.
When a car crashes what does it do and what does this cause?
Decelerates rapidly causing great forces due to the change in momentum.
