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```					                               Motion - Acceleration – 11.3

1. The rate at which velocity changes is called ____acceleration____.

2. Acceleration can be described as changes in __speed____, changes in __direction ___, or

changes in both.

3. Acceleration can be caused by positive ( _increasing______)change in speed or by negative

(__decreasing_) change in speed.

4. ___Deceleration_______ is an acceleration that slows an object down.

5. Free fall is the movement of an object toward Earth solely because of __gravity____. The unit for

velocity is meters/second. The unit for acceleration is meter/second/second. This measurement

is written as ___m/s2_.

6. Objects falling near Earth’s surface accelerate downward at a rate of _9.8 m/s2__.

7. Acceleration can be the result of a change in direction at __constant____ speed.

8. Sometimes motion is characterized by changes in speed and __direction___ at the same time.

9. The velocity of an object moving in a straight line changes at a constant rate when the object is

experiencing ___constant_____ acceleration.

10. How do you calculate acceleration? You divide the change in __velocity____ by the total time.

Acceleration is the rate at which velocity changes. V1 is the __initial_____ velocity and Vf is the

__final_____velocity and t is the total _time____.

The    means change.
11. If the velocity increases then the acceleration is __positive______. If the velocity decreases

then the acceleration is ____negative___.

12. Acceleration and velocity are both vector quantities. This means they have both speed and

direction. To determine a change in velocity, subtract one _velocity _ ___vector______ from

another.

13. A ball roll downs a ramp, starting from rest. After 2 seconds its velocity is 6 meters per second.

What is the acceleration of the ball?

What information are you given?
time = 2s
starting velocity = 0 m/s
ending velocity = 6 m/s
What unknown are you try to find? acceleration

Write the formula.

Fill in the formula with what you know and solve.

6 m/s - 0 m/s     = 3 m/s2 down the ramp
2s

14. The __slope____ of a speed-time graph is acceleration. ___Speed______goes on the vertical

axis and __time___ goes on the horizontal axis.

15. Constant acceleration is represented by a ____straight____ line. The slope of the line is the

_acceleration_______. This graph is a __linear__ graph.

16. Constant negative acceleration __decreases____ speed.
17. Accelerated motion is characterized by a ____curved____ line. In a nonlinear graph, a

_____curve__ connects the data points.

18. What is instantaneous acceleration? Instantaneous acceleration is how fast a velocity is

changing at a specific instant.

19. Acceleration involves a change in velocity or direction or both, so the vector of acceleration can

point in any ____direction_____. The vectors length depends on how fast __velocity_______is

changing. An object that is standing still has an acceleration velocity of _zero_______.

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