P2-3 Work, Energy And Momentum. Flashcards
How do you work out the amount of work done?
W=f x d
Work in j
Force in N
Distance moved in m
What happens when energy is transferred to an object?
It is able to move and WORK is done.
What happens to the work done to overcome friction?
It is given off as heat.
What does gravitational potential energy depend on?
The weight of the object and how much it moves vertically.
What is power and what is its formula?
The rate of energy transfer, p=energy
–––––––
Time
What has kinetic energy? And what is its equation?
All moving objects.
Ek(j)=0.5 x m(kg) x v*2 (speed in m/s)
What is an object named if it can regain its shape?
Elastic
What is elastic potential energy?
The energy stored once an elastic object is stretched or squashed. This energy is released once the object regains its shape.
When is momentum present?
Whenever an object is moving.
What is the equation for momentum?
P(kg m/s) = m (kg) x v (m/s)
What does the law of conservation of momentum state?
Whenever objects interact, the total momentum stays the same before and after the interaction.
What happens when two objects push each other apart? (Explosions)
They move apart at different speeds if they have unequal masses.
They move apart with equal and opposite momentum so the total momentum is 0
What happens when a force acts upon an object able to move?
Its momentum changes.
If the impact time is short, the forces on the object are…(complete sentence)
Large
What do side impact bars and crumple zones do in cars?
Increase the impact time by folding, reducing the forces on the car and people in it.
