Lesson 10 – Recap + calculations

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

1.4 Gravity

This lesson

•  Discussing the homework
•  Recap 1.4
•  Making calculations
• Worksheet mass and weight

Learning goals

• Explain the cause of gravity
  

• Describe the difference between mass and weight.

• Explain gravitational field strength

• Calculate weight, mass and gravitational field strength
  

Learning goals

• Be able to rearrange the forumla for weight and apply this in calculations.
  

• Learn a procedure for doing calculations.
  

Discussing the homework

Recap 1.4

Answer these 3 questions 

•  What is the cause of the force of gravity?

• Describe the difference between mass and weight.

•  What determines the gravitational field strength of a planet? What is its unit?

What is the cause of the force of gravity?

All masses exert a force on all other masses.

This force depends on:

•  the amount of mass
• The distance between the two masses

Describe The difference between mass and weight

Mass:

The amount of matter something is made off.

Weight:

The strength of the force of gravity on a specific object.

What determines the gravitational field strength of a planet? What is its unit?

The mass of the planet:

A planet with a larger mass exerts a larger attractive force on other masses.

Unit: N/kg

Un

weight=mass⋅gravitationalfieldstrenght

(N)

(kg)

(N/kg)

weight=mass⋅gravitationalfieldstrenght

(N)

(kg)

(N/kg)

weight=mass⋅gravitationalfieldstrenght

w=m⋅g

(N)

(kg)

(N/kg)

weight=mass⋅gravitationalfieldstrenght

w=m⋅g

• W: weight (N)
  
• m: mass (kg)
  
• g: gravitational field strength (N/kg)
  

(N)

(kg)

(N/kg)

w=m⋅g

6=3⋅2

w=m⋅g

6=3⋅2

Exercise

Rearrange the formula to use it to calculate:

a) mass

b) gravitational field strength

A procedure for doing calculations

1. Given
   
2. Asked
   
3. Formula
   
4. Calculation
   
5. Answer
   

Exercise

Procedure

1. Given
   
2. Asked
   
3. Formula
   
4. Calculation
   
5. Answer
   

A man has a weight of 813.4 N on earth. The gravitational field strength on earth is 

9.8 N/kg. Calculate his mass.

Worksheet mass, weight and gravitational field strength

• This is the homework for next lesson

Learning goals

• Be able to rearrange the forumla for weight and apply this in calculations.
  

• Learn a procedure for doing calculations.
  

Homework

The worksheet about mass, weight and gravitational field strength