kinematics Flashcards
what does savut stand for
s
a
v
u
t
DAFIT
D isplacement
A cceleration
F inal velocity
I nitial velocity
T ime taken
what are the SI units for savut
s
a
v
u
t
SI units
m
ms^-2 or m/s^2
ms^-1 or m/s
ms^-1 or m/s
s
constant speed = constant velocity
constant velocity ≠ constant speed
true or false, explain
true.
cuz speed is a scalar while velocity is a vector
speed means distance travelled per unit of time
velocity means the same but with the addition of direction
So, constant velocity implies both constant speed and constant direction, but constant speed alone doesn’t necessarily imply constant velocity if the direction of motion is changing.
e.g. a car goes in a circular track at a constant speed of 60km/h
speed is constant at 60km/h
velocity however is going up down negative and back to positive. like 2 semi circles
Distance definition
scalar or vector
length of path travelled by two positions
scalar
displacement definition
scalar or vector
charge in position of an object between two positions. In short, displacement may be viewed as distance in a specific direction.
vector
Speed definition
scalar or vector
distance travelled per unit time
scalar
velocity definition
scalar or vector
change in displacement per unit time
vector
acceleration definition
scalar or vector
change in velocity per unit time
vector
what does acceleration refer to
acceleration refers to the rate at which velocity is changing. this change can either refer to a change in magnitude or change in direction or both
y is the velocity time graph the most useful
it can obtain all 5 quantities savut
Displacement: Look at the area under the graph. The space between the graph and the time axis shows how far the object traveled.
Initial Velocity: read off
Final Velocity: read off
Acceleration: measure gradient
Time: read off
v u a t
v = u + (a)(t)
huat ah
s u v t
s = 1/2 (u+v)(t)
suv t
s u a t
s = (u)(t) + 1/2(a)(t)^2
plusle sUtat
s v t a t
s = (v)(t) - 1/2(a)(t)^2
minum sVtat
v u a s
v^2 = u^2 + 2(a)(s)
tuas view square
the 5 equations values
v u a t
s u a t
s u v t
s v a t
v u a s
what does positive constant a mean, and what does constant negative a mean
the velocity is increasing at a steady speed and is getting faster.
the velocity is getting slower
acceleration is defined as the rate of change of velocity or change of velocity over time.
write the formula for it to calculate acceleration
a = (v - u)/t
(v - u) is the change of velocity
how to represent constant on a graph
its a straight line
if speed is constant then velocity is? and acceleration is?
velocity is contstant, so acceleration = 0 (no acceleration)
acceleration can directly affect speed but speed cannot directly affect acceleration
t/f
true
how to express velocity when writing7
write the speed then the direction
how to get speed knowing that velocity is 20m/s
speed is the same as velocity without the direction so the speed is also 20m/s
What the approximate gravitational acceleration (g)
10m s^-2
(9.8 m s^-2)
Freefall definition
Motion of rising or falling object is only under the influence of gravitational forces
when can u use equations of motion
1d analysis where acceleration is constant.
Falling under air resistance
Motion of rising or falling object is under both gravitational and resistive forces by air
how to find average velocity
(f+i)/2
or
displacement (final position - initial position) / change in time (final time - initial time)
