Force Motion Review Problems Describe Speed A way

Force & Motion Review & Problems

Describe Speed • A way to describe motion – Average speed - Rate of motion calculated by dividing the distance traveled by the amount of time it takes to travel that distance – Constant speed - Speed that does not change – Instantaneous speed - Speed of an object at any given time

How is velocity different from speed? Velocity is speed in a specific direction. Examples: Ø The train was moving south at a rate of 45 km/hr. ØShe traveled 20 m/s north. § Speed: 55 m/hr § Velocity: 55 m/hr east

What is the formula used to calculate speed? Speed is calculated by dividing distance by time –

Calculate this Speed: A football field is about 100 m long. If it takes a person 20 seconds to run its length, how fast was the football player running? Speed = Distance ÷ Time Speed = 100 m ÷ 20 s Speed = 5 m/s Remember to include the UNITS!!

How far does a bicycle travel at a speed of 15 m/s for 15 seconds?

How far does a bicycle travel at a speed of 15 m/s for 15 seconds? D=Sx. T D = 15 m/s X 15 s D = 225 m

A swimmer swims 20 m in 40 s. What is the swimmer’s average speed?

A swimmer swims 20 m in 40 s. What is the swimmer’s average speed? S = D/T S = 20 m/40 s S = 0. 5 m/s

What is the average speed (mph) for a car journey of 120 miles that began at 09: 30 and finished at 12: 00 noon?

What is the average speed (mph) for a car journey of 120 miles that began at 09. 30 and finished at 12. 00 noon? S = D/T D = 120 T = 2. 5 hours (from 9: 30 – 12: 00) S = 120 m / 2. 5 h S = 48 mph