"The most incomprehensible thing about the world
is that it is comprehensible."

- Einstein

 

 



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

 

 

Ex 1) An object travels 5 meters in 2 seconds.

Find its speed.

 

Answer: Speed = d/t

 

 

= 5m/2 sec

 

 

 

= 2.5 m/s

 

 

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

 

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

 

 

 

 

 

 

 

 

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