Speed!

Speed (S) The distance an object travels in one unit of time.

Calculating Speed To calculate the speed of an object, divide the distance the object travels by the amount of time it takes to travel that distance.

Speed (S)= distance (d)/time (t) Formula for Speed Speed (S)= distance (d)/time (t) S=d/t Speed

km/s, m/s, cm/s km/h, m/h, cm/h Units For Speed km/s, m/s, cm/s km/h, m/h, cm/h m (distance)/s (time)

Constant Speed If the speed of an object DOES NOT CHANGE, the object is traveling at a constant speed. When an object travels at a constant speed, you know that its speed is the same at all times during its motion.

Formula for Constant Speed If you know the distance an object travels in a given amount of time, you can use the formula for speed to calculate the object’s constant speed. S=d/t

Average Speed Most objects do not move at constant speeds for very long. Most objects change their speed many times when they are in motion.

Calculating Average Speed To calculate the average speed of an object, you must know the total distance traveled and the total time the object traveled.

Formula for Average Speed Average Speed=Total Distance/Total Time

Distance (d) The space between two objects or points.

Tools to Measure Distance Meter Sticks Measuring Tape

Units for Distance Centimeters (cm) Meters (m) Kilometers (km) **REMEMBER: in science, we use the METRIC SYSTEM– your amazing science teachers don’t want to see units such as inches, feet, and miles!!!

Time Period of a given activity.

Tools to Measure Time Stop watch Clock ☺

Units for Time Milliseconds (ms) Seconds (s) Minutes (min) Hours (h) Days (d)

TRY IT! Calculate the speed for these objects: A car travels 66 kilometers in 2 hours, what is it’s speed? A car 200 kilometers in 5 hours, what is it’s speed?

TRY IT! Calculate the speed for these objects: A car travels 66 kilometers in 2 hours, what is it’s speed? 66 km = 33km/hr 2 hrs A car 200 kilometers in 5 hours, what is it’s speed? 200 km = 40 km/hr 5hrs