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Technology

Grade 7

Transport

Module 4

Finding the rocket’s centre of gravity

Assignment 1:

How to find your rocket’s centre of gravity

[lo 1.14]

Make a loop at the end of a 1 m piece of string.

  • Tie the loop around the body section of your rocket.
  • Let the rocket hang free in your hand and shift the loop until the rocket hangslevel/parallel to the ground.
  • Indicate the centre of gravity on the rocket by drawing a line right around the body with a marking-pen. Indicate the symbol for centre of gravity.

Background

The aerodynamic forces at a rocket’s centre of pressure are centred. The centre of pressure is usually also close to the tail end of the rocket. The large surface of the fins and the smooth surface of the rest of the rocket cause it to be the position where the pressure is the same on both sides. To get the centre of pressure closer to the tail of the rocket, the front section (nose) of the rocket has a more pointed shape or the body section of the rocket could be made longer, because in that way it becomes more aerodynamic. By putting smaller fins on the front section of the rocket, the centre of pressure is moved closer to the front end.

R ules : The centre of gravity should be closer to the front end of the rocket than the centre of pressure. The centre of pressure should be the same distance or longer than the diameter of the rocket from the centre of gravity to the tail end. This will make the rocket stable and will help it to fly in a straight line.

Assignment 2:

How to find a rocket’s centre of pressure

[lo 1.14]

Make a sketch of the side elevation of your rocket. Sketch the fins as well and draw as accurately as possible.

  • The centre of pressure is determined by drawing a line that spreads the surface of the rocket equally on both sides of the line.
  • Indicate the centre of pressure in the sketch by drawing a line through it.
  • Indicate the centre of pressure on the rocket by drawing a line right around the body with a marking-pen. Indicate the symbol for the centre of pressure.

Assignment 3:

Testing whether your rocket is stable during flight

[lo 1.13]

  • Make a loop at the end of a 2 m piece of string.
  • Tie the loop around your rocket at its centre of gravity. Affix the loop with adhesive tape if necessary.
  • The rocket should hang parallel to the ground surface (Sketch 1). Swing it around with a circular movement (Sketch 2).
  • Change the centre of gravity or the centre of pressure until your rocket swings forward in a straight line while hanging horizontally.

If you want to make any changes to your rocket to make it more stable, you can do it now. Decorate the bottles and fins so that it looks more like a rocket, for instance by painting it with an oil-based paint.

Now you are ready to launch your rocket.

Assessment

Learning outcomes(LOs)
LO 1
Technological processes and skillsThe learner will be able to apply technological processes and skills ethically and responsibly using appropriate information and communication technology.
Assessment standards(ASs)
We know this when the learner:
Evaluates :1.12 evaluates the product or system based on criteria linked directly to the design brief and some of the specifications and constraints, and suggests improvements or modifications;
1.13 evaluates the efficiency of the plan of action followed and suggests improving future plans;
Communicates :1.14 presents ideas (in a project portfolio) using two-dimensional or three-dimensional sketches, circuit diagrams or system diagrams.

Memorandum

Assignment 1 - 3

Learners can help each other to find the centre of pressure and centre of gravity of every rocket. They will differ seeing that the appearance of each rocket should differ.

Questions & Answers

where we get a research paper on Nano chemistry....?
Maira Reply
what are the products of Nano chemistry?
Maira Reply
There are lots of products of nano chemistry... Like nano coatings.....carbon fiber.. And lots of others..
learn
Even nanotechnology is pretty much all about chemistry... Its the chemistry on quantum or atomic level
learn
Google
da
no nanotechnology is also a part of physics and maths it requires angle formulas and some pressure regarding concepts
Bhagvanji
Preparation and Applications of Nanomaterial for Drug Delivery
Hafiz Reply
revolt
da
Application of nanotechnology in medicine
what is variations in raman spectra for nanomaterials
Jyoti Reply
I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
Damian
yes that's correct
Professor
I think
Professor
Nasa has use it in the 60's, copper as water purification in the moon travel.
Alexandre
nanocopper obvius
Alexandre
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
Rafiq
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
Damian
How we are making nano material?
LITNING Reply
what is a peer
LITNING Reply
What is meant by 'nano scale'?
LITNING Reply
What is STMs full form?
LITNING
scanning tunneling microscope
Sahil
how nano science is used for hydrophobicity
Santosh
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
Rafiq
what is differents between GO and RGO?
Mahi
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
Rafiq
if virus is killing to make ARTIFICIAL DNA OF GRAPHENE FOR KILLED THE VIRUS .THIS IS OUR ASSUMPTION
Anam
analytical skills graphene is prepared to kill any type viruses .
Anam
Any one who tell me about Preparation and application of Nanomaterial for drug Delivery
Hafiz
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
Renato
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
Adin
why?
Adin
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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Source:  OpenStax, Technology grade 7. OpenStax CNX. Sep 10, 2009 Download for free at http://cnx.org/content/col11032/1.1
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