<< Chapter < Page Chapter >> Page >

Natural sciences

Energy transfers and forces

A. forces

Educator section


Groups can assess each other’s dynamometers by determining how effectively they work. Compile a matrix in which the criteria that are to be assessed, as well as the criteria describers, are given. Allow the learners to join you in deciding about this, so that they will know exactly how the dynamometer will be assessed before the start of the project.

The weights of objects of which the weight will be determined will depend on the size of the objects that are used.


The greater the mass of the object, the greater the earth’s gravitational force upon it.

Let us test our knowledge:

(a) A force is exerted on an object, for example by pulling or pushing it.

(b) Newton (N).

(c) Dynamometer/spring-balance.

(d) E.g. 60 kg _______mass; then your weight is ± 600N seeing that 1 kg has the weight of ± 10N.

(e) Weight is the gravitational force of the earth on an object.

(f) Electrostatic force

Gravitational force

Magnetic force

(g) Tensile force

Momentum (thrust)

Rotational force/torque (torsion)

(h) A force can make an object rotate.

A force can halt a moving object.

A force can change the speed of an object.

A force can change the shape of a moving object.

A force can change the direction of a moving object.

(i) c

(j) Rotation

Leaner section


Activity: to build your own dynamometer [lo 2.4]

Build your own dynamometer


  • Wooden plank (30 mm x 300 mm)
  • Screw (± 25 cm in length)
  • Elastic band
  • Nail
  • Tin can lid
  • String
  • White paper
  • Retort stand and clamp

Step 1: Glue the white paper to the wood.

Step 2: Screw the screw in at the top of the plank.

Step 3: Suspend the elastic band from the screw and clamp the plank in the stand.

Step 4: Use the hammer and nail to pierce four holes at equal distances along the edge of the tin lid.

Step 5: Attach four pieces of string (each ± 150 mm long) to the lid, by tying them through the holes. Tie the four loose ends of string to another length of string (± 300 mm long). Then attach this longer length of string to the elastic band.

Step 6: Make a mark on the paper immediately below the elastic band. This is the O position.

Step 7: Now place the mass pieces (to a total of 102 grams) on the lid. Mark the new position of the elastic band as “1”.

Step 8: Repeat step 7, increasing the mass of the mass pieces as you proceed, until you have marked 5 graduations on the paper. Avoid putting too much strain on the elastic band – if it is stretched too far, it might snap.

You have now built a simple dynamometer calibrated in Newton. 1 N is equal to ± 102 g. One kilogram is therefore equal to approximately 10 N.

Use this dynamometer or another spring balance to determine the weight of the following objects:

one pen ______________________N
five such pens ______________________N
your shoe ______________________N
both your shoes ______________________N
an object of your choice ______________________N



The greater the___________________________________________, the greater the

Questions & Answers

what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
How we are making nano material?
what is a peer
What is meant by 'nano scale'?
What is STMs full form?
scanning tunneling microscope
how nano science is used for hydrophobicity
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
what is differents between GO and RGO?
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
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
The nanotechnology is as new science, to scale nanometric
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
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
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
what school?
biomolecules are e building blocks of every organics and inorganic materials.
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
sciencedirect big data base
Introduction about quantum dots in nanotechnology
Praveena Reply
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
Damian Reply
absolutely yes
how to know photocatalytic properties of tio2 nanoparticles...what to do now
Akash Reply
it is a goid question and i want to know the answer as well
characteristics of micro business
for teaching engĺish at school how nano technology help us
How can I make nanorobot?
Do somebody tell me a best nano engineering book for beginners?
s. Reply
there is no specific books for beginners but there is book called principle of nanotechnology
how can I make nanorobot?
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
what is the actual application of fullerenes nowadays?
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
Privacy Information Security Software Version 1.1a
Got questions? Join the online conversation and get instant answers!
Jobilize.com Reply

Get the best Algebra and trigonometry course in your pocket!

Source:  OpenStax, Natural sciences grade 7. OpenStax CNX. Sep 16, 2009 Download for free at http://cnx.org/content/col11077/1.1
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'Natural sciences grade 7' conversation and receive update notifications?