Describing Motion How to Describe Motion Words the

Describing Motion

How to Describe Motion Words - the car is traveling 30 m/s due east Equations and values - d/t = speed 100 m/20 s = 5 m/s Graphically -

With pictures

Vectors and Scalars A vector is a number with units and includes direction. Velocity is a vector - 130 mph West A scalar quantity is a number with units but does not specify the direction Speed is a scalar quantity - 130 mph

Vocabulary Reference point - a zero point Position - separation of object and reference point Distance - separation of two objects or locations, needs no reference point. Displacement - distance and direction between two positions

Calculating Motion Ave. Speed = total distance s=d/t total time Ave. Velocity = total displacement v = d/t total time Or velocity 1 + velocity 2 2 only if traveling at each velocity for the same amount of time This does not give you instantaneous speed or velocity.

When calculating average speed or average velocity, can the instantaneous speeds change along the way? Units for speed are m/s or cm/s or km/h If velocity is known, you can calculate distance. Δd = vt or df = di + vt

3 Step Method 1) Write out the equation s = d/t 2) Substitute in your values with units s = 30 m/10 s 3) Write out answer with units. s = 3 m/s

A car travels 450 m in 9. 0 seconds find the average speed of the car. A train is traveling 45 km/hr east for 2. 5 hrs. Find the displacement of the train. A person on a bike is traveling 20 m/s for 10 s and then speeds up to 50 m/s for 10 s. Find the ave. speed of the bike. A person on a bike is traveling 20 m/s for 100 m and then speeds up to 50 m/s for 100 m. Find the ave. speed of the bike.