# Speed 4th Grade science S4P3b.

## Presentation on theme: "Speed 4th Grade science S4P3b."— Presentation transcript:

What is speed?  Speed is a measurement of how fast an object moves relative to a reference point. It does not have a direction and is considered a magnitude or scalar quantity.

Speed can be figured by the formula:
Speed = Distance/Time  or  s = d/t

How to Measure Speed  In the United States we mostly think of speed in miles per hour or mph. This is the way the speed of a car is typically measured. In science and physics the standard unit of measure for speed is generally meters per second or m/s.

Speed Average Speed S = d / t T = d / s D = s x t
Comparison of time and distance A scalar quantity [magnitude only] Distance traveled per unit time S = d / t T = d / s D = s x t

Speed Instantaneous Speed
Speed at any instant

Speed Constant Speed Speed that does not change
Instantaneous speed that does not change

What causes speed? Speed is caused by a force.

Forces Pushes or pulls May cause acceleration [changes in motion]
May also cause changes in shape