1. Speed, Velocity, and Acceleration
Chapter 5

2. Speed
Distance traveled divided by the time it takes to travel that distance
Speed = distance
time
Sample units: m/s, km/h, km/s, m/h
If a car travels 30 km in 5 hours, what was the car’s speed?

3. Velocity Speed of an object in a specific direction
To calculate velocity you would use the formula for speed and then include the direction in which the object is traveling

4. Is this a speed or velocity measurement?
A car traveled at 10 km/hr.
A plane traveled north at 48,000 km/hr.
A cheetah ran 5 km/hr north and then turned around and headed south.

5. Calculate Speed A marathon runner completed 10 km in 2 hours.
A car traveled 500 km in 6 hours.
A cheetah ran 25 km in 5 hours.
A plane traveled 1000 km in 10 hours.

6. Calculate Average Speed
Remember to use the complete distance and complete time.
Average Speed = total distance
total time
A family takes a car trip. They travel 80 km in an hour. After a pit stop, they travel another 70 km in 2 hours. What is their average speed?

7. Calculate Average Speed
If a car travels 50 km in 3 hours and then travels another 100 km in 2 hours, what is the average speed of the car?
If a train travels 150 km in 2 hours and then after it stops to pick up new passengers it travels another 200 km in 3 hours, what is the average speed of the train?

8. An object accelerates if:
Speed changes (faster or slower)
Direction changes
Both speed and direction change

9. Are the following objects accelerating?
A car goes 50 km/h to the north.
A car changes its speed from 25 km/h to 100 km/h.
An eagle travels at 25 km/h to the north and then turns around and flies south.

10. Acceleration Acceleration is the rate of change of velocity over time
Acceleration = final velocity - starting velocity
time
Sample units: m/s2, km/h2
Since acceleration is a change in velocity you have to include a direction

11. Calculate Acceleration
A cheetah traveling south accelerates from 20 m/s to 34 m/s in 7 seconds.
An eagle traveling east accelerates from 15 m/s to 22 m/s in 4 seconds.

12. Calculate Acceleration
A car traveling to the west decelerates from 100 km/hr to rest in 2 hr.
A cheetah running south goes from 40 m/s to rest in 5 seconds when it spots its prey.