Speed Speed S The distance an object travels

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.

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

Units For Speed km/s, cm/s km/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 = 33 km/hr 2 hrs – A car 200 kilometers in 5 hours, what is it’s speed? 200 km = 40 km/hr 5 hrs