8+9: Space, Time and Motion Flashcards
(40 cards)
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