1. BY
MBILI N.E (201083646)
AND
DUBAZANA N (201062405)

2. There are four Fundamental Forces of Nature

3.  Nuclear Force – is the strong attractive force between nucleons in the atomic nucleus
that holds the nucleus together.
 They are attractive in character.
 They are charge independent.
 It is the short range force.
 They are extremely strong.
 They are dependent on the on the spin of the nuclei.

4.  Electromagnetic Force - is the force that causes the interaction between electrically
charged particles, and the areas in which this happens are called electromagnetic fields.
 Binds atoms and molecules together to form ordinary matter
 It is so much stronger than the Gravitational Force
 Obeys a Universe square law
 Operates between over the distance which are not very large.
 It is the long range force, in principle extending over infinite distance

5.  Gravitational Force – is the force that holds all the objects onto the earth.
 The gravitational force can also be describes as the force of attraction between all
masses in the universe, especially the attraction of the earth’s mass for bodies near
its surface.
 It holds the planets, stars and galaxies together.
 It exists where ever there’s matter.
 It’s related to weight, the gravitational force is directly proportional to the weight.

6.  The weak Force- The fundamental force that acts between leptons and is involved in
the decay of hadrons.
 It is responsible for nuclear beta decay (by changing the flavour of quarks) and for
neutrino absorption and emission.
 It is mediated by the intermediate vector bosons (the W boson and the Z boson).
 It is weaker than the strong nuclear force and the electromagnetic force but stronger
than gravity.
 it is only effective at very short distances (10-18 m).
 Beta decay is just one example of the weak force, During beta decay a neutron
disappears and is replaced by a proton, an electron and a neutrino (anti-electron).
 If the weak force were not to exist, many types of matter would become much more
stable.
 Without the weak force, the sun would cease to exist. The weak force allows the
fusion of protons and neutrons to form deuterium. The excess energy from this fusion
is the source of heat from the sun.

7. THE GRAVITATIONAL FORCE - In order to calculate the gravitational force between two
objects with masses of m1 and m2 , the equation is:

8. ELECTROMAGNETIC FORCE - The force of attraction (or repulsion) of two particles
can be calculated using Coulomb’s law. The law states:

9. THE WEAK FORCE
Beta decay is just one example of the weak force. During beta decay a neutron disappears
and is replaced by a proton, an electron and a neutrino (anti-electron). It is also proven
that a down quark disappears and an up quark is produced. The up quark eventually turns
into the electron and neutrino. This can all be illustrated using the diagram below.

10. In order to be considered part of our universe an object must interact by means of one
of the four forces. The identity of a particle is, in a sense, determined by what forces
it can respond to. Gravity acts on mass-energy which all particles (even the massless
photon) possess. Everything responds to gravity. Quarks, the heaviest constituents of matter,
respond to all of the remaining three forces. Quarks are defined as those particles that
possess strong, weak and electromagnetic charge. Charged leptons (such as electrons and
muons) interact both weakly and electromagnetically. Finally the interaction-impoverished
neutrinos (neutral leptons) possess only weak charge; the neutrino interacts only via gravity
and the weak force.

11. 1. Davies, Paul (1986), The Forces of Nature, Cambridge Univ. Press 2nd ed.
2. R. Machleidt and I. Slaus, "The nucleon–nucleon interaction", J.
Phys. G 27 (2001).
3. G.D. Coughlan, J.E. Dodd, B.M. Gripaios (2006). The Ideas of Particle Physics:
An Introduction for Scientists (3rd ed.). Cambridge University Press. ISBN 978-0521-67775-2.
4. http://www.mosaicsciencemagazine.org/pdf/m10_05_79_01.pdf
5. "Sir Isaac Newton: The Universal Law of Gravitation". Astronomy 161 The
Solar System. Retrieved 2008-01-04.