Zusammenfassung der Ressource
Work, energy and momentum
- key points
- Energy and work
- Work is done on an object when a
force makes the object move
- Work done to overcome friction is
transferred as energy that heats the objects
that rub together and the surroundings
- Energy transferred =
- Word done
- Work done (joules) =
- force (newtons) x distance moved in the
direction of the force (metres)
- Kinetic energy
- The kinetic energy of a moving
object depends on its mass and its
speed
- Elastic potential energy is the energy
stored in an elastic object when work is
done on the object
- Kinetic energy (J) =
- 1/2 x mass(kg) x speed(m/s/s)
- Gravitational potential energy
- The gravitational potential energy of an object
depends on its weight and how far it moves vertically
- The change of gravitational potential energy of an object
is equal to its mass x the gravitational field strenght x its
change of height
- The gravitational potential energy of an
object increases when the object goes up
and decreases when the object goes down
- Momentum
- Momentum =
- mass x velocity
- The unit of momentum is kg m/s
- Momentum is conserved whenever objects interact, provided the
objects are in a closed system so that no external forces act on
them.
- Enter text here