Y2_T4_LSN_4.2

• Science
• Middelbare school
• havo, vwo
• Leerjaar 2

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• Your Macbook (join the LessonUp)
• Your notebook.
• Your textbook.
• Pen & highlighter

Topic 4

Moving in the world

Plan for today

• Explanation T4.2 Speed
  
• Make homework
  

4.2 Speed

Learning goals

I can....

• describe the concept of speed and understand which measurements and units are necessary to calculate it
• calculate the speed (or distance or time) of an object using the speed formula
• convert speed between the units of m/s and km/h
• create and interpret s,t-diagrams relating to an object's motion

Key words

• Speed
•  s,t-diagram

Speed

The speed of an object tells us how far it moves in a certain amount of time.

It is calculated with the following formula:

distance can be calculated with the following formula

1. s = v/t Distance = speed / time
2. s = t/v distance = time/ speed
3. s = v x t distance = speed * time
4. t = s x v time = distance * speed

time can be calculated with the following formula

1. t= v/s time = speed / distance
2. t = s/v time = distance /speed
3. t = s x v time = distance * speed
4. t = s + v time = distance + speed

Units of speed

The speed can be given in 2 different units:

• m/s (meters per second)
• km/h (kilometers per hour)

Speed question

Calculate the average speed of the green car (in m/s)

Speed question

In the first 3 hours the green car 

rode a distance of 60 km

so : 

s = 60 km 

t = 3 hours

Speed question

FICA:

F: v = s/t

I:  s=60  t=3

C: v= 60/3 = 20 (km/h)

     v = 20/3,6

A: v = 5,6 m/s

Convert 100 km/h to m/s?

1. 27,8 m/s
2. 360 m/s
3. 103,6 m/s
4. 96,4 m/s

convert 18 m/s to km/h

1. 14,4 km/h
2. 65 km/h
3. 5 km/h
4. 21,6 km/h

s,t-diagram

An s,t -Diagram is a graph that shows the movement of an object.

it shows the distance (s) and the time (t)

s,t-diagram

What does this graph tell you?

s,t-diagram

In the first 25s the object is moving 200 m

In the second 20s the object has stopped

In the last seconds the object is coming 

back a 100 m

How far is the object after 16 seconds?

1. 500 km
2. 1000 km
3. 0 km
4. 300 km

What is the speed of the object at 11 seconds?

1. 0 m/s
2. you can't tell
3. 500 m/s
4. 500 km/h

Homework

• Study the glossary of 4.2
  
• Complete the exercises of 4.2 (p. 166-111)