Work and energy looks at GPE, KE and elastic energy, and how they are conserved. It also looks at the relationship between force and extension, as well as how car features absorb energy in a crash.
How do we calculate work done?
Work done = mass × distance moved
Work done = force ÷ distance moved
Work done = force × distance moved
What are the units for work done?
What would the work done be when a 1 kilogram book is carried up a flight of stairs 15 metres tall?
What is work done a measure of?
The transfer of energy
The force used to move an object
The distance an object moves when a force is applied to it
How do we calculate gravitational potential energy on Earth?
Weight × height
Force × height
Mass × height
How do we calculate kinetic energy?
m × v2
distance ÷ time
0.5 × m × v2
Which of these increases the kinetic energy of a car the most?
Doubling the mass
Doubling the velocity
They are the same
What amount of gravitational potential energy would be gained when a 1 kilogram book is carried up a flight of stairs 15 metres tall?
When an elastic object is stretched, the increased length is called its extension. What is the relationship between the extension of the object and the force applied to it?
The extension of an elastic object is inversely proportional to the force applied to it
The extension of an elastic object is directly proportional to the force applied to it
The extension of an elastic object is directly proportional to the force applied to it squared (x ∝ F2)
As well as seat belts, what other car features absorb kinetic energy?
Bumpers and windscreens
Brakes and central locking
Airbags and crumple zones