Questions and memo answers for pencil-paper task of On the Moon Applet:
Elizabeth van Rooyen 20470622
Dona van Eeden 20063415
Question levels according to CAPS: L1; L2; L3; L4
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ON THE MOON
Question 1:
What do you weigh on other planets?
(10 marks)
Your weight is: ______________ kg.
Table 1:
Planet Name
Mercury
Venus
Earth
Moon
Mars
Jupiter
Saturn
Uranus
Neptune
Equation
.38 x _____ (your weight)
.9 x _____
1 x _____
.17 x _____
.38 x _____
2.36 x _____
.92 x _____
.89 x _____
1.12 x _____
1.1 On which planet do you weigh the least? L1
-
(1 mark)
Planet that corresponds to the students’ lowest weight
1.2 On which planet do you weigh the most? L1
-
My New Weight
(1 mark)
Planet that corresponds to the students’ highest weight
1.3 Will a cinder block with the weight of 20 kg on Earth fall slower on the moon or on Earth if
dropped from the same height? Justify your answer. L4
(2 marks)
-
The block will fall slower on the moon because the gravitational pull is lower on the moon
than it is on the Earth.
Question 2:
2.1 Based on the equation W = m × g how would you describe the relationship between mass and
weight? L3
(2 marks)
Students should refer to the fact that weight is directly determined by the mass of an object and that
it is influenced by the gravitational pull of where the mass is. This allows them to think about what
the formula means in stead of just plugging in values and getting an answer.
2.2 Astronauts on a research station on the moon have received a big box of peanuts from NASA.
They weigh it and see that the peanuts weigh 50kg on the moon. What is the mass of the peanuts?
If it costs R16,70 for 1kg of peanuts, how much did the peanuts cost when NASA bought it to send
up to the moon? L3
(4 marks)
-
Mass is _
50kg on moon is _ kg on Earth
So _ * R16,70 =
This seems like a simple question, but without explicitly stating that the students should base the
cost on what the peanuts weigh on earth, it goes a bit deeper. Students must realise that the 50kg
on the ISS will be a different weight on earth and form their calculations based on that. In this case
they pause and reflect on the concepts of weight and mass and gravity. They also have to retrieve
the info on how to calculate weight on the moon from the table in a previous questions.
2.3 Do you think you weigh more at sea level or at the top of Mount Everest? Explain why you
think so. L4
(2 marks)
-
You will weigh more at sea level because you are closer to the earth’s core that causes
gravitational pull. On the mountain you are the furthest away from the core that you can get
while still being on earth.
Question 3:
Another way to calculate weight also known as an attraction force between two objects that can be
calculated with equation 𝐹 =
-
𝑀𝑚
𝑑2
where:
F = force
M = mass of the large object
m = mass of the small
d = the distance between the centres of the small object and the large object
3.1. In Table 2 the M and m values remain the same, but the distance between objects change.
Describe what will happen with the F value. Justify your answer with calculations. L4 (12 marks)
Table 2:
Force (F)
100
50
33,33
25
20
Big mass (M)
50
50
50
50
50
Small mass (m)
20
20
20
20
20
Distance2 (d2)
10
20
30
40
50
3.2. In the scenario where the M and d2 values remain the same, but m change. Describe what will
happen with the F value. Justify your answer with calculations. L4
(6 marks)
- The learners will use their own calculations to reason and observe that as m increase, so does the
value of F ; or calculate as m decrease, so will value of F.
3.3 What would you expect to happen with a change in big mass? Explain your answer. L3
(2 marks)
- As big mass increase, the value of force will increase as well like it has with an increase in values of
small mass.
3.4 Explain the relationships between the variables of the force equation. L4
(3 marks)
- Force and distance has an inverse relationship where if force would increase or decrease, the
opposite would happen with distance and vice versa if small mass and big mass remains constant.
If either or both big mass or small mass would increase or decrease, the same trend will be observed
with the force if the distance2 remains constant.
Question 4:
Planet D
M=7
Planet A
D2=2
M=20
Planet B
D2=4
M=70
D2=25
Planet C
M=12
D2=5
4.1 Using equation W = m × g (where g = 9,8) calculate the mass of person A that weighs 90kg on
earth. L2
(2 marks)
m=
90
= 9,184
9,8
4.2 What would the weight of Person A be on Planet C? L2
𝐹=
𝑀𝑚
𝑑2
𝐹=
12 × 9,184
= 22,04
5
(2 marks)
4.3 If force is the same on each planet, how would the mass of person A have changed on each
planet? Answer with increase, decrease, the same. Justify your answer. L4
(8 marks)
- Planet A: 22,04 =
𝑚=
22,04∗4
20
20 × 𝑚
4
= 4,41 therefore decrease
Planet b: 𝑚 =
25 × 22,04
70
Planet c: 𝑚 =
5 × 22,04
12
= 9,18 therefore the same
Planet d: 𝑚 =
2× 22,04
7
= 6,3 therefore decrease
= 7,87 therefore decrease
-
This question requires learners to reason by making calculations to determine and support
their answer.
4.4 Will planet A be more drawn to planet C or the planet D if their centres are at an equal
distance from each other? L3
(1 mark)
- Planet C
4.5 How far from each planet should you put planet B to have the same pull force from the rest of
the celestial objects? Illustrate the position of planet B. L4
(8 marks)
- Learners need to analyse the information and reason the distance of planet B from other planets
e.g.: if force = 1 then
o Distance between planet A and B will be
Mm
 𝑑2 = 𝐹
20×70
o
 𝑡ℎ𝑒𝑟𝑒 𝑓𝑜𝑟 𝑑2 = 1 = 140
 𝑡ℎ𝑒𝑟𝑒𝑓𝑜𝑟𝑒 𝑑 = 11,83
Between B and C:
Mm
 𝑑2 = 𝐹

o
𝑑= √
B and D:
 𝑑2 =

𝑑=
Mm
𝐹
Mm
𝐹
Mm
√
𝐹
= √
70×12
1
= √
70×7
1
= 100,4
= 58,57
C
100,4
B
D
58,57
11,83
A
4.6 A new planet (Planet D) is found with a d2 value of 22 and a mass of 500. Calculate the weight
of the astronaut that weighs 100 on planet A. L3
(3 marks)
o
100 =
o
𝑚=
70×𝑚
4
100×4
20
= 20
(Learners calculate the astronauts mass on planet A and insert into equation of weight for Planet D)
o
𝐹=
50000×20
22
=
1000000
22
= 45 454,55
4.7 A box has 20 potatoes where the box ways 5 kg on planet B. How much will this box weigh on
Planet D. L2
(3 marks)
- 5= (70×m)/25
Therefore: m= (5×25)/70= 125/70=1,7857
Calculate mass to calculate new weight
F= (1,7857×500) / 22 = 40,5844 = 40,58
4.8 The astronaut is only able to carry a weight of 40 at a time.
4.8.1 When there is a delivery of 30 boxes on planet D, how many times will the astronaut carry
boxes from the delivery vehicle to the storage? L4
(4 marks)
o 30 x 40,58 = 1217,4
o 1217,4 / 40 = 30,435
o Therefore he will carry 31 times.
4.8.2 Explain how the astronaut will carry the boxes without going over the weight he is able to
carry.L4
(2 marks)
Learners need to come up with a (creative) solution and explain their solution.
e.g.:
- He will pack the boxes for each weight, using an old box to carry the final potatoes.
- He will use a contraption to push the boxes on.