Lesson 3— More indepth on calculating speed

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

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​​

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 

Converting m/s to km/h​

1m/s is how many km/h?​

1m/1s = 0.001km/1:3600h​= 3.6km/1h​

So 1m/s = 3.6 km/h​

Converting km/h to m/s​

1km/h is how many m/s

1km/1h =1000m/3600s​​

1km/h = 1000:1000 m/3600:1000 s​​

1km/h = 1 / 3.6 m/s

So 1km/h = 1/3.6 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?

72: 3.6 = 20 m/s

Exercise

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

7* 3.6 = 25.2 km/h

km/h —> m/s

The speed : 3.6

m/s —> km/h

The speed x 3.6

Exercise

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

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

38:3.6= 10.56 m/s

1.5* 3.6 = 5.4 km/h

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

A car is travelling 40 km/h. the distnace travelled is 400 km. Calculate the time.