Zusammenfassung der Ressource
Nat 5 Physics
Dynamics and Space
- Space
- A satellite is an
object which orbits
another object
- Vectors and Scalars
- Average speed is
the distance per
unit time
- speed= distance /time
- Instantaneous speed is the
average speed of something
over a small distance
- speed=distance/time
- Scalar Quantities are defined
by magnitude (size) only
- Scalar Quantities
include distance,
speed, time, mass,
energy and volume
- Vector quantities are defined
by magnitude and direction
- Vector Quantities
include displacement,
velocity, acceleration,
force and weight
- Distance is a
scalar quantity
and displacement
is a vector
- Displacement is
the distance and
the direction
- ALWAYS add
vectors nose to tail
- Velocity is the speed of
something in a particular
direction
- velocity =
displacement/
time
- Acceleration is the
change in velocity
per unit time
- Acceleration= final
velocity-initial
velocity/ time
- If a car is
slowing
down the
acceleration
is negative
- The area under a
speed time graph
is the distance and
the area under a
velocity time graph
is the displacment
- Newtons Laws
- Force can change the speed,
direction or shape of an object
- Unit of force is Newtons (N)
- Forces are vector (direction and size)
- Mass is the amount of matter that
an object has and weight is the
force that gravity exerts on an
object- weight is a force
- Gravitational
field strength is
the weight per
unit mass
- weight= mass x
gravitational field
strength
- Earth 9.8 N/kg
- Friction is a resistive
force which opposes
the motion of an
object
- Friction is a force which
acts between two rough surfaces
- Friction can be decreased
by lubricating the surfaces,
separating the surfaces
and streamlining
- Friction can be increased
by choosing surfaces which
cause high friction and
increasing surface area and
choosing shape to increase
air friction
- Newtons 1st Law - an object
in motion stays in motion
and an object at rest stays at
rest unless acted on by an
unbalanced force
- no force is equivalent
to equal forces
- For a moving
object if the forces
are balanced then
it will move at a
constant velocity
- For an object at
rest if the forces
are balanced it
will not move
- Newtons 2nd Law- if an
unbalanced force acts on an
objects then the object will
accelerate in the direction of
the force
- The greater the resultant force
the greater the acceleration
- The smaller the mass the
greater the accelaration
- Unbalanced Force=
mass x acceleration
- The acceleration of something
falling vertically is always 9.8m/s^2
- Newtons 3rd Law - For
every action there is an
equal and opposite reaction
- Forces occur in pairs.
These two forces are
always equal in size but
opposite in direction
- If object A exerts a force (the
action) on object B then object
B will exert an equal and
opposite (reaction) force on
object A
- F1=--F2
- A projectile is an object that has
been given a forward motion but
which is also pulled dowards by
the force of gravity this results in
the path being curved
- Projectile has both
horizontal and
vertical motion
- A projectile travels at a
constant speed
horizintally and a
constant acceleration
downwards (9.8)