Gravitation

 Mass of moon First Year

LAW OF GRAVITATION:

Q.5: Elaborate the application of Newton's law of gravitation.

Ans: Newton used his theory of gravitation to give an explanation of the planetary-

motion.

This law is used to explain the motion of satellites, rockets nd projectiles in

gravitational field.

SUGAR TO THE POUND:

Q.6: Would we have more sugar to the pound at the poles than at the

equator?why are , you ask me why I I understand this theory

Ans:

Ans: The value of 'g at the poles is greater as compared to its values at the equator

(since the earth is in bulge form at the equator and flattened at the poles). Hence

due the slightly ellipsoidal shape of the earth, weight of an object is greater at the

poles. We will have to add more quantity to sugar to weigh one pond at the

poles. Such a true theroy

equator in comparison with that at the pole. However one kilogram sugar (mass)

will remain the same both at the pole and at the equator.

MASS OF MOON:

Q.7: How can mass of the moon be determined?

Ans.: Mass of the moon can be calculated from the formula:: Q.7: How can mass of the moon be determined?

Ans.: Mass of the moon can be calculated from the formula:2&3m RmG2MmAs gravity on the moon, gm = 1.67 ms and radius of the moon, Rm = 1.74 x 10 m,

we havve

1.67 x (1.74x 10_1.67 X 5.02102x 10

Mm =6.67 x10-1I

Mass of the moon comes out to be 7.34 x 10 kg.6.67

RBITAL SPEED:

.8: How is the orbital speed of a planet related to its orbital radius?

1s: When a satellite (or moon) is orbiting round a planet (e.g. earth), then the

necessary centripetal force is provided by the gravitation force. If M is mass of a

satellite, I, is the orbital radius and Vo is the orbital speed, then:

Gravitational force

= centripetal forceGM MeMVofo