# Lesson 7

Chapter 2 Forces
Section 3 Driving forces and resisting forces
This Lesson
• Discussing exercises
• Newtons first law
• Air resistance
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Slide 1: Slide
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This lesson contains 10 slides, with text slides.

Lesson duration is: 45 min

## Items in this lesson

Chapter 2 Forces
Section 3 Driving forces and resisting forces
This Lesson
• Discussing exercises
• Newtons first law
• Air resistance

#### Slide 1 -Slide

Discussing section 2

exercise 5 and 6

#### Slide 2 -Slide

Practice exercise
On an experimental setup on the moon a weight with a mass of 5 kilogram is hung on a spring with a spring constant of 0,45 N/m. Calculate the extension of this spring.

Voyager 2

#### Slide 6 -Slide

Newtons first law
If the resultant force of all the forces is zero (0N), the object is either stationary or it moves along a straight line at a constant speed

#### Slide 7 -Slide

Air resistance
Fr,a=21CdρAv2
• Fr,a: Force, resistance, air resistance (n)
• C: resistance coefficient (no unit)
• ρ: The density of air (or whatever medium the object is traveling through) (kg/m3)
• A: area of the object (m2)
• v: the speed of object (m/s)