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Description
Mind Map by thegeekymushroom, updated more than 1 year ago
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Created by thegeekymushroom
almost 10 years ago
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P4: Explaining motion
- Speed - the distance traveled in
a certain time
- distance x time
- The speed of an object is
unlikely to be the same
- it is often more useful to work out the
average speed of a journey
- distance x time
- Velocity has direction
- it is often more useful
measurement of motion
- e.g. 30 mph due north
- if two objects move
in opposite directions,
one has positive
velocity and the other
has negative velocity
- e.g. one would be
20 m/s and the
other -20 m/s
- e.g. one would be
20 m/s and the
other -20 m/s
- it is often more useful
measurement of motion
- Acceleration - how
quick you're speeding
up
- change in velocity / time taken
- the change in velocity (whether it be
+ve or -ve) within a certain amount
of time
- unit is m/s2
- is a result of unbalanced
forces (thrust is greater than
drag)
- for example, a rocket taking off has a
greater amount of thrust than it does
gravity or drag, otherwise it would fail to
lift off
- the greater the resultant force,
the greater the acceleration.
- for example, a rocket taking off has a
greater amount of thrust than it does
gravity or drag, otherwise it would fail to
lift off
- change in velocity / time taken
- forces of motion
- friction and drag
- friction is the force
that opposes
movement
- they are reaction forces - they
happen as a result of an applied
force
- the frictional force will be equal to the force of movement
up to the maximum point where the friction will be
overcome and the object will move
- there is friction between solid
forces which are gripping, this
allows you to stand and walk
e.t.c
- there is also friction between two solid
surfaces moving past each other, this can be
reduced by adding a lubricant like oil
- drag, sometimes called resistance, is the
equivalent to friction in gases and liquids instead of
solids, so a streamline object would find it easier
to move as it would be less effected by drag
- friction is the force
that opposes
movement
- thrust
- thrust is the force that
opposes drag and friction
- for an object
to increase its
speed, thrust
must be greater
than drag
- thrust is the force that
opposes drag and friction
- reaction force/
lift and weight
- an object on a
surface pushes
down because of its
weight
- the reaction force comes
from the surface and equals
the weight, if it cannot do
this, the object will fall
through the surface
- lift is the equivalent of reaction force in the
air for example with planes - it helps to keep
the plane at a constant altitude
- an object on a
surface pushes
down because of its
weight
- for an
object to
travel at a
constant
speed, the
forces must
be balenced
- Resultant force is the
overall force acting on
an object
- friction and drag
- Momentum - how hard it is to stop an
object from moving
- mass x velocity
- Change in
m0mentum
- dependent on the force
- when a resultant force acts on an
object, it causes a change in
momentum
- the change in momentum is
proportional to the size of the
force and the time it acts for
- resultant force x time for
which the force acts
- dependent on the force
- mass x velocity
- Work - "work done" =
"energy transferred"
- when a force moves an object it
does work and energy is
transferred to the object
- amount of energy transferred (J) =
Work done (J)
- the object doing the work
transfers the energy
therefore losing energy
- not all the energy is transferred to the
object having the work done, some is lost
through other means, e.g. sound and heat
- the object doing the work
transfers the energy
therefore losing energy
- work done by a force (J) = force (N) x
distance moved in the direction of force (m)
- when a force moves an object it
does work and energy is
transferred to the object
- Gravitational potential energy - 'Height Energy'
- Kinetic energy - the
energy of movement
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