Speed

• Science
• Secondary Education

SPEED

GRADE-9

sept 22, 2020

STARTER 

Which car will be in first position?

and what about second and third position?

OBJECTIVES 

1. Define speed

2. Differentiate constant and changing speed

3. Calculate speed

SPEED

Speed is the distance an object moves divided by the time it took to move that distance

Speed=  distance travelled /time taken 

How are these two different?

Constant speed - when the distance travelled is same during each second

Changing speed- when the distance travelled is not the same during each second

What is speed?

1. How fast or slow an object moves
2. A kind of drug
3. Is moving faster and faster
4. A type of game

Identify the speed -constant or changing

What are the two terms associated with speed ?

1. time, distance
2. time, direction
3. direction, distance
4. reference point, time

Identify this as constant speed or changing speed? Imagine it is the same car

RECALL 

It takes Ahmed 50 s on his bicycle to reach his friend' house 250 m away. What is his average speed?

A truck driver makes a trip that covers2,380 Km in 280 hours. What is the drivers' average speed?

CHALLENGE -Aaron leaves one city at noon. He has to be at another city 186 km away at 3:00 P.M. The speed limit the entire way is 65 km/hr. can he arrive second city on time

Challenge  - During which period did the object slow down 

Which term describes the motion in the time period from 3 to 5 seconds?

A. at rest

B. constant speed

C.slowing down

D. speeding up 

Two things you understood today