Y10 Forces 1 Flashcards
forces are _____ represented by ______
vector quantities
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Newtons First Law
a body at rest will remain at rest unless acted upon by a resultant force
a body in motion will remain in that motion unless acted upon by a resultant force
Newton’s third law
for every action (force) there is an equal and opposite reaction (force)
weight
mass x gravitational field strength
newton’s second law
f = ma
for a dropped object (with no air resistance):
a = g (m/s2)
work done =
force x displacement (m)
E = F x d
what is work done
energy transferred when you move something
measured in joules
power =
work / time
power measured in
watts
why does neil DG tyson know the ball won’t hit him
“initial GPE = maximum energy of the system (if no externally added energy)”
- law of conversation of energy
therefore the highest the ball can go is where Neil releases it from
stores of energy
kinetic
elastic PE
chemical
GPE
electrostatic
magnetic
thermal
nuclear
4 energy transfers
mechanical work - forces
electrical work - potential difference
heating - temperature diff.
radiation - as a wave
energy transfers:
bow and arrow
simple circuit w/ a bulb
elastic PE, mechanically, kinetic
chemical, electrically, thermal, radiation
(change in) GPE =
mass x gravitational field strength x (change in) height
OR
weight x height
kinetic energy =
1/2 x mass x speed squared
acceleration =
v-u / t
change in velocity / t
how to calculate acceleration without time
v2 - u2 = 2as
final velocity - initial velocity = 2 x acceleration x displacement
why is an object moving at a constant speed in a circle accelerating
acceleration = vector
object is changing direction
example of centripetal force
car on a roundabout
force is from friction between tyres and road
inertia
a property of matter by which it continues in its existing state of rest or uniform motion in a straight line, unless that state is changed by an external force
