energy and forces Flashcards
gravitation potential energy store
when any object with a mass is in a gravitational field
what does g measure?
gravitational field strength ( N/kg )
what will happen to GPE if you double the height of an object?
GPE is doubled
GPE = ?
mgh
GPE unit
J ( joules )
KE =
mv* / 2
Kinetic energy store
object that has mass and is moving
closed system
an object/s that energy cannot leave or enter
law of conservation of energy
energy cannot be created or destroyed
dissipation
when energy is transferred, some is transferred to thermal store of surroundings
why does dissipation occur?
friction between object and air
forces
all matter interacts with other matter due to forces
forces are always interactions between how many objects?
2
what can a force do to an object?
push or pull
forces are vector quantities
they always have a magnitude and a direction
gravitational force
between all objects with a mass ( non-contact )
normal force
right angles to the surface ( contact )
tension
stretched object exerts force on the object pulling it ( contact )
friction
2 surfaces moving in direction opposite to motion ( contact )
air resistance
air pushes on object against direction of motion ( contact )
water resistance
water particles act in opposition to object’s motion ( contact )
upthrust
force on bottom of object is directed upwards ( contact )
thrust
engine provide forwards force ( contact )
magnetism
between magnets and magnetic materials, repulsive or attractive ( non-contact )
