Unit I - Mechanics - Study of the relationship between force and motion
I. Kinematics - Mathematical methods of describing and predicting motion
We can describe and predict the motion of objects with:
Motion Diagrams
(plots of motion information)
• equations
II. How do we describe motion?
Speed
Acceleration
Velocity
(speed and direction)
III. What do we measure when we study
motion?
Distance
(meter ≈ 1 yard)
Time
(seconds)
Direction
A. Speed - how much distance an object covers per unit time
1. Speed = distance / time
a) Units - m/s, km/hour, miles/hour
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Ex 1) An object travels 5 meters in 2 seconds. Find its speed. |
Answer: Speed = d/t
= 5m/2 sec
= 2.5 m/s
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Ex 2) An object moves at a rate of 3 m/s for 1.5 seconds. How far did the object move? |
Answer: Speed = d/t
3 m/s = d/1.5 sec
d = 4.5 m
Photos made by
Eadweard Muybridge (1830- 1904)
Animation by User
Waugsberg
Public Domain
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Ex 3) An object moves at rate of 4 m/s over a distance of 10 meters. How long did it travel. |
Answer: Speed = d/t
4 m/s = 10 m/t
(Cross Multiply)
(4 m/s)t = 10 m
(Divide by 4)
t = 2.5 seconds
| © Tony Mangiacapre., St. Mary's HS, Manhasset, NY-All Rights Reserved [Home] Established 1995 |