Motion Type Uniform Motion1型匀速运动.pptVIP

Motion Type 1: Uniform MotionWhat is Uniform Motion? Uniform motion describes an object travelling at a constant speed in one direction Characteristics of Uniform Motion 1) Distance: A measure of length Base unit is the meter or “m” Displacement: The length that an object has moved from a starting reference point In physics, when we talk about distance, we are really referring to a change in distance Change in distance = final distance – initial distance Or… ? d = df - di Characteristics of Uniform Motion 1) Distance Change in distance example: If Mr. Okrainetz starts at rest and travels 3.5m, what is his change in distance? Use: ? d = df – di df = 3.5m di = 0 m ? d = 3.5m – 0m ? d = 3.5m Characteristics of Uniform Motion 2) Time Change in time example It took Mr. Okrainetz 1.1s to travel his distance from rest Use ? t = tf – ti tf = 1.1s ti = 0s ? t = 1.1s – 0s ? t = 1.1s Characteristics of Uniform Motion 2) Time A measure of duration Base unit is the second or “s” In Physics when we talk about time, we are really referring to a change in time Change in time = final time – initial time Or… ? t = tf - ti Characteristics of Uniform Motion 3) Velocity A measure of a specific distance travelled in a specific amount of time Velocity = change in distance change in time Or… v = ? d ? t Base unit for velocity is meters per second or “m/s” Characteristics of Uniform Motion 3) Velocity Example of velocity Based on the previous two examples, how fast was Mr. Okrainetz travelling? Use v = ? d ? t ? d = 3.5m ? t = 1.1s v = 3.5m 1.1s v = 3.18 m/s or sig fig correct answer = 3.2 m/s * * * * * * * * * * * * * *