content analysis

SYMBOLS

 d,a ,g, G, T,v ,r, M, m, F

TERMS

Speed, Force, , Gravitational Pull, Gravitational Force, Vector quantity, Acceleration, Mass, Frictional force, orbit, orbital velocity, Centripetal force, velocity, acceleration due to gravity, weight. Free fall, Contact and Non Contact forces

FACTS:

1.When you throw a ball up in air it will falls down

2.We can stand on earth without falling

3. A mango falls down from a mango tree.

4.Artificial satellites revolving around the earth is where the force of gravity is experienced.

5.Gravitation keeps us walking on Earth instead of floating away into space

6.Gravitational force depends on distance and mass of a body

7.At the center of the earth you feel weightless.

 8.Gravitational force is responsible for the revolution to the Moon around the Earth.

 9.Gravity is responsible for water to rest at the bottom of a glass instead of hovering over at the top the glass

10.All bodies on earth are attracted towards the centre of earth.

11.If we drop two bells of the same size but different weights from a rooftop, they would hit the ground at the same time.

12. If a feather and a coin is dropped from the same height, feather took more time to reach the bottom due to air resistance.

13.On a giant wheel ride, a person experiences loss of

weight on the descent.

14.To leave gravitational pull behind, an object must

Travel 7 miles a second, our planet escape velocity.

15.Crews of space craft are subject to the problems of

Weightlessness.

16.The gas in the sun are held together.

17.Leaves and fruits fall from a tree downwards towards the ground

18.The objects present on the surface of the earth do not float in the air.

19. A child can slides through a slide

20. The drinks poured in a glass stay to the base and do not rise up to the brain.

21.Rocks and other objects placed on a slanting surface tend to roll down if no obstacles are present in the path.

22.The rain on the snow falls directly on the ground and does not float on the air.

CONCEPTS:

1.The earth attracts all objects towards its centre This force of attraction is the force of gravity.

2.Mass of a body is the amount of matter contained in it

3.On earth all bodies have a weight or downward force of gravity.

4.Gravity is the universal force of attraction between all matters.

5.Weight is a measure of the gravitational force pulling objects toward Earth

6. Acceleration due to gravity is the acceleration caused by the gravitational attraction of massive bodies

 7.Acceleration due to gravity doesnot depend on the mass of the body. It will be the same for all bodies falling to earth.

8. A free fall occurs when a body is allowed to fall from a certain height, it falls to the earth due to force of gravity.

 9.Weightlessness is the complete absence of the sensation of weight

10.Gravity is a natural phenomena that applies to anything with mass energy

11.Gravity is far weaker than the other three fundamental forces.

12.bjects seem “weightless” when there is nothing holding them up!

13.Astronomers use the law of gravity to analyse distant phenomena.

DEFINITIONS

1.The force of gravity – The earth attracts all objects towards it’s Centre. This force of attraction is the force of gravity.

2.Mass – mass of a body is the amount of matter contained in it

3.Acceleration due to gravity – acceleration due to gravity does not depend on the mass of the body. The acceleration of a body free fall under the influence of earth’s gravity expressed as the rate of increase of velocity per unit of time is defined as the acceleration due to gravity.

4 Free fall— When a body is allowed to fall from a certain height it falls to the earth due to the force of gravity. This is known as free fall.

FORMULAE

The force of mutual attraction between two bodies

F = G m1m2/d^2

Acceleration due to gravity – g = GM/R^2

Weight of a body, F = mg

LAWS:

Universal Law of gravitation- According to the Universal low of gravitation, the force of mutual attraction between two bodies is directly proportional to the product of their masses and inversely proportional to the square of the distance between them.

Kepler’s first Law of Motion-Planets revolve in elliptical Orbits around the sun.

Kepler’s second Law Motion -The line joining the planet And the sun sweep equal areas in equal intervals of time.

Kepler’s third Law of Motion- The cube of the mean distance of a planet from the sun is directly proportional to the square of its orbital period