1.4 gravity

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

§1.4 Gravity

Gravity

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
  

What is the cause 

of gravity?

See the video, figure out what their final conclusion is on what gravity is. Write it down after the video.

Attractive force between any two object with mass.

The difference between 

mass and weight

Mass and weight

Mass

• How much matter something is made of
• does not change with location
• Measured in kg

Weight

• the force of gravity acting on a specific object
• Depends on the gravational field strength something is in
• Measured in newton

• all mass applies an attractive force on all other mass. The gravitational force.
  

• the strength of this attractive force depends on the amount of mass (in kg) and the distace.
  

• The more mass something is made of, the greater its gravitational force is on other masses.
  

The larger the distace the lesser  the force of gravity.

 

• the amount of newtons a body of mass applies to other masses per kilogram is called its gravitational field strength (N/kg)
  

Gravitational force

Is the force experienced(in N) per unit mass by an object. And is measured in (N/kg)

Gravitational field strength

The amount of newtons a body of mass applies to other masses per kilogram (N/kg)

Gravitational field strength

For example:

The gravitational field strength on Earth is 10 N/kg. Means a mass of 1 kg experiences a force of 10 N.

The gravitational field strength on Jupiter is 23 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)

	11.3 kg	21.7 kg	44.8 kg
Weight (N) On earth
Weight (N) On mars
Weight (N) On planet Z	135.6	260.4	537.6

Weight = mass x gravitational field strength

See the table on the right.

a) fill in the weight of the masses on earth and mars.

b) calculate the gravitational field strength of planet Z

Gravitational field strength earth = 10 N/kg

Gravitational field strength mars = 3.7 N/kg

	11.3 kg	21.7 kg	44.8 kg
Weight (N) On earth	113	217	448
Weight (N) On mars
Weight (N) On planet Z	135.6	260.4	537.6

Weight = mass x gravitational field strength

See the table on the right.

a) fill in the weight of the masses on earth and mars.

b) calculate the gravitational field strength of plante Z

Gravitational field strength earth = 10 N/kg

Gravitational field strength mars = 3.7 N/kg

	11.3 kg	21.7 kg	44.8 kg
Weight (N) On earth	113	217	448
Weight (N) On mars	41.81	80.29	165.76
Weight (N) On planet Z	135.6	260.4	537.6

Weight = mass x gravitational field strength

See the table on the right.

a) fill in the weight of the masses on earth and mars.

b) calculate the gravitational field strength of plante Z

Gravitational field strength earth = 10 N/kg

Gravitational field strength mars = 3.7 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

	11.3 kg	21.7 kg	44.8 kg
Weight (N) On earth	113	217	448
Weight (N) On mars	41.81	80.29	165.76
Weight (N) On planet Z	135.6	260.4	537.6

Weight = mass x gravitational field strength

Calculate the gravitational field strength of planet Z

Gravitational field strength earth = 10 N/kg

Gravitational field strength mars = 3.7 N/kg

Homework

Workbook exercises 1.4

Exercise 1, 2, 3 and E

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