speed and velocity
TRANSCRIPT
Speed and velocityApril 12, 2023
Copy and complete the following table:
Quantity Symbol Unit Symbol Equation
Speed
Distance
Time
Quantity Symbol Unit Symbol Equation
Speed vmetre per second
m/s v=d/t
Distance d metre m d=vt
Time t second s t=d/v
time
distancespeed
Definition
• Speed is the rate of change of distance
time
distancespeed
t
dv
221
r
mGmmg
Why I don’t like formula triangles
Now stick that in a triangle…
Can you calculate speed?
• Usain Bolt can run 100 m in 9.58 second. How fast does he run?
Worked example
1-ms OR m/s 44.10
58.9
100
?
58.9
100
v
s
mv
t
dv
v
st
md
Two types of speed
• How fast was Usain Bolt running at the start?
• How fast was he running in the middle?
• How fast was he running at the finish?
Average speed
taken timetotal
travelleddistance totalspeed average
Instantaneous speed
• This is the speed at any given moment (or instant!)
• A speedometer in a car gives the instantaneous speed but you would have to calculate the average speed (most GPS systems can do this for you)
Displacement
• The difference between the starting point and finishing point. It is distance with direction
How far does a football travel during a match?
• Distance: many kilometers
• Displacement: 0
Velocity
• The rate of change of displacement
• OR
• How fast you are going in a particular direction
Velocity
t
sv
Graphing movementApril 12, 2023
Learning objective
• Draw and interpret distance-time graphs
• Draw and interpret velocity-time graphs
Define these terms…
• Distance
• Displacement
• Speed
• Velocity
The Moving Man
To do
• Using graph paper draw a distance-time graph of your journey to school
• Now try a velocity-time graph of the same journey