8+9: Space, Time and Motion Flashcards
example of vectors
out of: mass, displacemt, force, temperature,velocity time, length, acceleration, speed, energy, momentum
displacement, force, velocity, acceleration, momentum
suvat equation u,v,t,a
v=u+at
suvat equation s,u,v,t
s= t x (u+v) x 1/2
suvat equation s,u,t,a
s= ut + (1/2x at^2)
suvat equation s,v,t,a
s=vt - (1/2x at^2)
suvat equation v,u,a,s
v^2 = u^2 +2as
what do you need to make sure when something is travelling downwards (either a, u, v, s)
if it’s downwards it could be a negative
question where something is thrown from the top of a cliff
you calculate the vertical distance
what equation do you use to find the horizontal
s=d/t
a displacement/time graph that shows acceleration will always be
curved
a displacement/time graph with constant velocity
will be a straight line
acceleration=
(v-u)/t
how to find the distance traveled on a speed/time graph
area under graph
advantages of data loggers
more accurate data- cancels out human reaction time
higher sampling rate (ten readings a second)
data displayed in real time
work
force x distance
work measured in
Joules
It is energy that has been changed from one form to another
Power (rate of doing work) x3
P =work/time (P= FxD/t)
P =Force x Velocity
P= E/t
watt units
Js^-1
if calculaing lifting work dont forget
to times by gravity
efficiency=
useful energy output / energy input
Kinetic energy=
1/2mv^2
Gravitational potential energy
mass x gravity x height
mgh
Elastic potential energy
1/2ke^2
k- stiffness constant
e- extension
if you need to find something but you dont have enough parts (you have height and gravity) what two equations can you rearange
mgh=1/2mv^2
the masses can then be cancelles
How to improve measuments
Repeat measurement, take an average (removes random error)
higher precision apparatus (cuts random error)
Calibration- compare value to a known value
units for kinetic energy
kgm^2 s^-2
units for acceleration other than ms-2
Nkg-1
if there is a squared in an equation
the graph will be curved
work done=
force x distance
force=
ma
Work / distance
why can you onlly see some wavelengths after diffraction
because destructive interference occurs
it can only be one wavelength or the other
Transverse:
oscillations/vibrations in direction perpendicular
to direction of movement of wave (1);
Longitudinal:
oscillations/vibrations in direction parallel to
direction of movement of wave (1)
which can be measured in J
W= Fs or P= Fv
W
F, W, P, V^2, S
which are vectors
S and F
units for force
kgms-2
units for energy, Joules
Nm
J
prefix of wavelength of light
10^-6
prefix weight of a person in N
10^3
why the colour of the incident light and increasing its intensity causes different amounts of electrons to be emitted (evidence of quantum behaviour)
energy needed liberate electrons
higher f (>L) means higher energy photons
light provides energy in packets
one photon emits one electron
same wavelengths only are energetic enough
w=Fs
units
Joules
