Lesson 4 — More indepth on calculating speed

• Natuurkunde / Scheikunde
• Middelbare school
• havo
• Leerjaar 1

Lessonplan

Lesson plan

Opening

Class phase

Solo phase

Closing

Learning goals

Mention at the end of the lesson that you will check the homework next lesson

Lesson plan

• Rearranging the formula for speed
  
• Converting km/h <-> m/s
  
• Exercises on calculating speed

Goals

• Know how to rearrange the formula for speed
• Know how to convert km/h <-> m/s

Class Phase

Speed:

How fast something is moving

Average speed

total distance divided

by total time

Steady speed

Traveling at a constant speed

Formula for speed

Speed=​time​​distance​​

Formula for speed

Speed=​time​​distance​​

v=​t​​d​​

Formula for speed

Speed=​time​​distance​​

v=​t​​d​​

v: velocity

d: distance

t: time

Rearranging the formula for speed

v=​t​​d​​

3=​2​​6​​

Rearranging the formula for speed

v=​t​​d​​

Speed: 

Distance:

Time:

Rearranging the formula for speed

v=​t​​d​​

Speed: 

Distance:

d=v⋅t

Time:

Rearranging the formula for speed

v=​t​​d​​

Speed: 

Distance:

d=v⋅t

Time:

t=​v​​d​​

Converting 

km/h <-> m/s 

Exercise

• A car travels 72km/h. What is that in m/s?
  
• A cyclist travels 7 m/s. What is that in km/h?

Exercise

• A car travels 72km/h. What is that in m/s?

• In one hour the car travels 72km = 72000 m
• One hour = 3600 seconds
• So in 3600 seconds it travels 72000 m
• Then in 1 second it travels 72000/3600 = 20 m/s
• So a speed of 72km/h converts to 20 m/s

Exercise

• A cyclist travels 7 m/s. What is that in km/h?

The cyclist travels 7 meters in one second

There are 3600 seconds in one hour

So in one hour the cyclist travels 7m x 3600 = 25200m

25200m = 25.2 km. the cyclist travels 25.2 km in on hour.

So a speed of 7 m/s converts to 25km/h.

km/h —> m/s

The speed x 1000/3600

m/s —> km/h

The speed x 3600/1000

Exercise

Convert a speed of 38 km/h to m/s

Convert a speed of 1.5 m/s to km/h

km/h —> m/s

The speed x 1000/3600

m/s —> km/h

The speed x 3600/1000

Exercise

Convert a speed of 38 km/h to m/s      =      10.55 m/s

Convert a speed of 1.5 m/s to km/h      =      5.4 km/h

km/h —> m/s

The speed x 1000/3600

m/s —> km/h

The speed x 3600/1000

Solo Phase

Exercises on 

calculating speed

Goals

• Know how to rearrange the formula for speed
• Know how to convert km/h <-> m/s

Next lesson

Homework:

Complete the worksheet