INTRO TO LINEAR MOTION

What is a rate?• A rate tells us how fast something happens, or how much

something changes in a certain amount of time.

• For example, a quantity divided by time (miles per hour -- mph)

Speed• Speed is a rate.

• Speed – a measure of how fast something is moving. It is the rate at which distance is covered.

• Units: miles/hr, m/s, km/hr

Instantaneous vs average

• Instantaneous speed is the speed at a given instance. • For ex: The speed on a car’s speedometer

• Average speed does not indicate variations in the speed that may take place during a trip. Instead, it is the total distance covered divided by the total time.

Average speed

Average speed =Total distance covered

Time interval

Speed vs. Velocity• The ball is passed to you

during a football game. What do you do?

• Velocity is speed plus direction.

Constant & Changing Velocity• Constant velocity is when both the speed and direction

are constant.

• If either the speed or direction (or both) are changing, then the velocity it changing.