Science Study Guide Motion – Speed, Velocity, Acceleration

I. Vocabulary

We’ve come across and have been using many terms in the last few weeks related to motion. You should be able to explain what the terms mean in your own words.

motion reference point distance speed rate constant speed average speed velocity slope acceleration

Remember: acceleration is the rate at which velocity changes. Example: a car accelerates 4 miles/hour/second

This means, a car will increase its velocity by 4 miles per hour during each second of acceleration.

II. Formulas (think of formulas as recipes – a fixed method of accomplishing something)

During our study of motion, we had to calculate the speed of rolling science fair cars, the average speed of horses, and the acceleration a rolling ball goes through as it rolls down a wobbly wooden ramp. Here are the formulas we’ve been using:

Formula Formula (in words) (using symbols)

distance d speed = ------s = ------time t

total distance traveled average speed = ------total time

final velocity – initial velocity vf – vo acceleration = ------a = ------time t

distance = velocity x time d = v t

1 1 distance = x acceleration x time 2 d = a t 2 2 2

III. Units

Speed isn’t measured in apples. Distance is not measured in cars. Acceleration isn’t measured in square meters. So, what are the units for the stuff we’re studying?

Remember: the ‘/’ is said as “per”

Distance – examples: feet, yards, meters, kilometers, centimeters, millimeters, etc.

Speed – units of distance per units of time units of distance / units of time

examples: miles per hour kilometers per hour centimeters / minute inches / second

Acceleration – units of velocity per units of time units of distance per units of time per units of time

examples: meters per second per second feet per second 2 kilometers per hour per second

IV. Graphing - visual representation of what’s going on

Distance versus Time (also can be said as “Distance as a Function of Time”)

Points on a graph – the location of an object at a particular time.

Slope – a measure of how slanted a line is. The slantyness tells you the speed.

Straight lines – a line with constant slant; it represents motion at a constant speed.

Curved lines – represents motion where distance traveled by an object varies each unit of time.