Zusammenfassung der Ressource
Motion,Force,moments levers and centre of
gravity
- Motion
- Speed
- the distance travelled by an object in one unit if time
- distance divided by time
- the units of speed are m/s or m/s _1
- velocity
- units of velocity are m/s or m/s-1
- distance divide by time
- speed in a given direction
- acceleration
- the change in speed divided by the time taken for the change
- final speed-first speed dividedby th time taken
for the change in speed
- units of acceleration are m/s2 or ms-2
- force
- causes a stationary object to move
- unit is newton=N
- types of resources:magnetic force,electric
force,force of gravity,force of friction
- Friction
- a force tha opposes the sliding motion
of an object when in contact with
another
- advantages:slows you are going to fast in a car.slows you
down when you are going to fast on a bicycle.needed when walking.
- disadvantages:can give you blisters when walking in
new shoesmore fuel is needed in a car bacause
when air hits a car it is friction.wears away parts of
cars or bicycle
- reduce friction by lubricants such as oil
- graph in hard back on difference
between weight and mass
- hookies law:the extensin of an
elastic body(a spring)is directly
proportional to the force causing
the extension
- moment,levers and centre of gravity
- calculating the moment of a force=forcw multiplied by perpendicular
distance from fulcrum to the line of action of the force
- levers
- a ridgid body that can turn about a fixed point called fulcrum
- study page 292
- eg:scissors,wheelbarrow and door
- law of the lever is when a lever is
balanced the sum of the clockwise
moments equals the anticlockwise
moments
- centre of gravity
- the centre of gravity of an object is a point in the object
through all the weight of an object appears to act.
- equilibrium
- when an object is balanced and
still,the object is called equilibrium
- the three stages of equilibrium
- stable equilibrium:the ball will return to
the same position if given a slight push
- unstableequilibrium:the ball will not ruturn to
the same position if given a slight push
- neutral equilibrium:the ball will to a similar position is
given a slight push