Les 14

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

Today's lesson

• Discussing the homework
• Finishing §1.4 Gravity
• Handing in the report

Goals

• Apply the formula for weight.
• Explain the difference between mass and weight.
• Name the unit for mass and for weight. 

Discussing

the homework

Link

Find a way to	Describe how you did so.	balanced or unbalanced forces?	What happens to the speed of the cart?
The cart stand still and keeps standing still	...
Get the cart to start moving	...
Get the cart to move at a steady speed.	...
Ge the cart to slow down when it is already moving.	...

Question 5  — Net force

Find a way to	Describe how you did so.	balanced or unbalanced forces?	What happens to the speed of the cart?
The cart stand still and keeps standing still	...	Balanced	Stays the same
Get the cart to start moving	...	Unbalanced	it increases
Get the cart to move at a steady speed.	...	Balanced	stay the same
Ge the cart to slow down when it is already moving.	...	Unbalanced	it decreases

Question 5  — Net force

For applied to the box (In Newtons)	Force of friction	Does the box move (yes/no)
0
50
100
150
200
250
300

Question 2

For applied to the box (In Newtons)	Force of friction	Does the box move (yes/no)
0	0	No
50	50	No
100	100	No
150	150	No
200	200	No
250	250	No
300	188	Yes

Question 2

question 3

Finishing § 1.4

Gravity

What does the image tell you about mass and weight. Explain.

What is the unit of mass?

1. Kilogram
2. meter / seconds
3. Newton
4. Liter

What is the unit of weight?

1. Meter / second
2. Meter
3. Kilogram
4. Newton

Give a description for mass and for weight.

The Earth has about 10 times the mass of Mars. On which planet can you jump higher? Explain.

Mass on Earth	Weight on Earth (N)	Mass on the moon	Weight on the Moon (N)	Mass on the planet	Weight on the planet (N)
50 g					2.5
500 g					25
2 kg					100
25 kg					1250

Mass on Earth	Weight on Earth (N)	Mass on the moon	Weight on the Moon (N)	Mass on the planet	Weight on the planet (N)
50 g	0.5	50 g	0.08	50 g	2.5
500 g	5	500 g	0.8	500 g	25
2 kg	20	2 kg	3.2	2 kg	100
25 kg	250	25 kg	40 N	25 kg	1250

b) 50 N/kg

c) More, because it's gravitational field strength is stronger

Gravitational field strength earth = 10 N/kg

Gravitational field strength mars = 3.7 N/kg

	10 kg	20 kg	50 kg
Weight (N) On earth
Weight (N) On mars

Weight = mass x gravitational field strength

Gravitational field strength mars = 10 N/kg

Gravitational field strength mars = 3.7 N/kg

	10 kg	20 kg	50 kg
Weight (N) On earth	100	200	500
Weight (N) On mars

Weight = mass x gravitational field strength

Gravitational field strength mars = 10 N/kg

Gravitational field strength mars = 3.7 N/kg

	10 kg	20 kg	50 kg
Weight (N) On earth	100	200	500
Weight (N) On mars	37	74	185

Weight = mass x gravitational field strength

Link

Goals

• Apply the formula for weight.
• Explain the difference between mass and weight.
• Name the unit for mass and for weight.