Speed and Velocity

Speed and Velocity
What is meant by the terms:
Speed?
Velocity?
Keywords: Speed, Velocity
is just how fast you are going with no regard to the direction.
Must have the direction specified as well as the speed.

Speed and Velocity
Are these examples of speed or velocity?
Keywords: Speed, Velocity,
30 mph
Speed
30 km/h north
Velocity
15 cm/s
Speed
10 m/s, 0600
Velocity
So:
Speed and velocity are both measured in the same units and say how fast you are going.
Velocity though gives you the direction too.

Speed and Velocity
You need to be able to calculate the speed of an object. What do you need to know? (think about the units of speed).
Keywords: Speed, Velocity,
How far something has travelled - distance
How long it took to travel that distance – time.
Remember: Speed is measured in mph, km/h, m/s, cm/s

Speed and Velocity
So the formula to work out speed is:
Keywords: Speed, Velocity,
Remember: Speed is measured in mph, km/h, m/s, cm/s
So the answer is in the units:
Distance = Speed
Time
d
t
s

Speed and Velocity
So the formulas are:
Keywords: Speed, Velocity,
d
t
s
Speed = Distance Time
Time = Distance
Speed
Distance = Speed x Time

Speed and Velocity
Lets use the formulas:
Keywords: Speed, Velocity, Acceleration,
d
t
s
A cat walks 20m in 35s. Find:
Its speed
How long it takes to walk 100m
1a. Speed = Distance = 20m
Time 35s
Answer: 0.57 m/s (remember units)

Speed and Velocity
Lets use the formulas:
Keywords: Speed, Velocity, Acceleration,
d
t
s
A cat walks 20m in 35s. Find:
Its speed
How long it takes to walk 100m
1b. Time = Distance = 100m_
Speed 0.57m/s
Answer: 175s (remember units)

Speed and Velocity
Lets use the formulas:
Keywords: Speed, Velocity,
d
t
s
To calculate velocity, we use the same formula.
All that we would need to add is the direction that the cat was walking.