1. Motion describes a change of position. Speed describes a change of position in a specified time.
2. You need distance (change in position) and Time (the time required to change position) to
calculate speed.
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5. The speed is the slope of a line on a distance vs. time graph. You can find the slope by using rise
(change in position) over run (change in time).
6. A flat line on a distance vs. time graph shows a situation when the distance doesn’t change with
time so the speed is zero!
7. Velocity includes a direction and speed does not. Traveling 45 miles per hour north is a velocity.
Traveling 45 miles per hour is a speed.
8. Change in velocity over time is called ACCELERATION. It can be a change in speed or a change in
direction.
9. To Calculate acceleration, you need to know the change in velocity. To find the change in
velocity you need the final velocity (V final) and the initial velocity (V initial).
10. Acceleration is the slope of a velocity vs. time graph because rise over run is equal to change in
velocity/change in time.
11. Zach could calculate speed using the speed formula (see question #6) OR he could plot distance
and time data and calculate the slope using “rise over run” or the change along the Y axis
divided by the change along the x axis.
12. The speed of the car that Sydney is riding in is EQUAL to the speed of the car that Ashlee is
riding in.
13. If you know that the speed is changing, and you only have a starting and stopping time and
distance information you can only calculate the AVERAGE speed Jake is traveling.
14. Jeremy is putting more effort in pedaling the BMX bike; this will cause his speed to increase
because he is accelerating in the direction of his motion.
15. We can use the speed triangle to find out how long it will take Markus to run 100 meters if his
speed is 15 m/sec. To find time, you divide the distance by the speed, so it would take 6.67
seconds.
16. Speed in a specific direction is called velocity.
17. Acceleration measures change in speed or direction.
18. A change in position over time is called speed.
19. To find speed, Alexis must know the distance traveled by her friend and the time it took to travel
that distance.
20. Scott and Brock have the same speed, but opposite velocities since they are traveling in
opposite directions.
21. Zero Acceleration describes the situation when the velocity is constant (it does not change).
22. The graph line would be horizontal showing that speed does not change which would be zero
acceleration.
23. When you subtract the initial velocity from the final velocity and divide the time that it takes to
change the velocity you are calculating ACCELEREATION.
24. a) Mariah’s average speed is 8.44 m/sec.
b) No her speed increased. You can tell because the slope of the line gets steeper after about 14
seconds.
Mariah's speed while running at track
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Time (sec.)
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