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Physics > Gravitation > Flashcards

Gravitation Flashcards

1
Q

state Newton’s law of gravitation?

A

every body in the universe attracts every other body with force directly proportional to the product of their masses and inversely proportional to the square of the distance between their centres.

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2
Q

what is G?

A

universal gravitational constant
its value =6.673 × 10-11 Nm2 kg-2

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3
Q

G is _______________ proportional m1 m1

A

directly

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4
Q

G is _____________ proportional to d2

A

indirectly

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5
Q

What is the difference between the gravitational force and the force of gravity?

A

Gravitational force acts between any two objects possessing mass.
Force of Gravity is a natural property of the earth due to which it attracts all objects near to it.

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6
Q

what is F according to Newton’s law of gravitation?

A

F= G m1 m1/ d2

gravitational force of attraction

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7
Q

mass of earth?

A

6×10^24 kg

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8
Q

how do we find mass of the earth?

A

page 110

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9
Q

formula for mass of the earth?

A

mE= gr2/G

g= gravitational accelerarion
r= distance or radius of the earth
G= gravitational constant

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10
Q

what is gravitational field strength?

A

the gravitational force per unit mass.

how much gravitational force a body 1kg experiances.

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11
Q

what is gravitational field?

A

a region in space around a massive object where other objects with mass experience a force of attraction due to gravity.

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12
Q

g=
what is the value of g at the surface of earth?

g = gravitational field strength

A

F/m
10N/kg

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13
Q

what is the radius of earth?

A

6.4x10^6 m

this is in meters in kilometers it would be 6,371 km

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14
Q

the weight of an object on the earth is the result of __________________.

A

gravitational force of attraction b/w the Earth and the object.

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15
Q

to find the mass of a planet what do we need to know?

A

gravitational acceleration
radius

same for star

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16
Q

why acceleration due to gravity is same as gravitational field strength?

A

Newton’s 2nd law of motion
a=F/m
g= F/m

a is force per unit mass.(how much force causes acceleration.)
g is gravitational force per unit mass experiances.

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17
Q

gravitational force =?

A

weight

18
Q

can there be different value for gravitational acceleraration?

A

yes
At the poles, you’re closer to the center of the Earth, so the gravitational force is a bit stronger.
At the equator, you’re farther away from the center because of the bulge, so the gravitational force is slightly weaker.
FMIGTN

less radius = more force

19
Q

does g depend on upons mass of the body?

g= gravitational acceleration

A

g=G Me/re2

in this equation g does not depend upon mass of the body

20
Q

what does gravitational acceleration depend upon?

A

radius of the earth
mass of the earth
g= G Me/re2

21
Q

what is the formula for acceleration due to gravity at a height h?

A

gh= G Me/(R+h)^2

22
Q

does gravitational acceleration decrease with increasing altitude?

A

No, g decreases but not with altitude.
gravitational force between two objects is inversely proportional to the square of the distance between them. As you move farther away from the Earth’s center, the distance between you and the center of the Earth increases, leading to a decrease in gravitational force and, consequently, a decrease in gravitational acceleration.

23
Q

what is a satellite?

A

naturally occruing or man-made object that orbits another object larger than itself by force of gravity.

24
Q

what is orbital velocity?

A

in circular orbit, a satellite has a constant tangential speed called orbital velocity.

25
Q

why the speed of a satellite should be kept constant and at stable speed?

A

high speed= move in elliptical orbit or escape.
low speed = fall back to Earth

26
Q

formula for orbital velocity?

derive it?

A

v=√Gme/re + h

27
Q

orbital speed doesn’t depend upon ___________.

A

mass of satellite

28
Q

altitude of geostationary orbit?

A

35,700 km

29
Q

when finding orbital speed, the radius which is ____________should have matching units in m.

A

sum of Earth’s radius and height of satellite

always remember that!

30
Q

why Earth doesn’t move towards the object becuase of its gravitational force?

A

the vast difference in mass b/w the Earth and typical objects.
object’s mass is minuscule compared to the Earth’s mass, so the acceleration of the Earth caused by its gravitational attraction is immeasurably small.

31
Q

difference b/w gravitational force and universal gravitational constant?

A

gravity is the force itself
the universal gravitational constant is a numerical value that helps us calculate the strength of that force.

32
Q

Gravitational acceleration decreases when _________________.

A

you move farther away from the center of the Earth.

decreases with increase in altitude.

33
Q

why is a satellite put into a circular orbit?

A

becuase in a circular orbit, a satellite has a CONSTANT tangential speed.

which is called orbital velocity.

34
Q

how to put a satellite in an orbit?

A
  1. move it to a high altitude.
  2. accelerate it to a required constant tangential speed using rockets.
35
Q

prove that gravitational acceleration of heavy or light object is same?

A

g=GMe/Re2

this shows that g doesn’t depend upon mass of the object but mass of the earth & distance b/w their centers.

36
Q

the change in the value of g is significant only ________________.

g= gravitational acceleration

A

at large distances.

37
Q

define gh?

A

value of acceleration due to gravity at a height ‘h’ from the surface of the Earth.

38
Q

what is the formula and value of the orbital velocity of a satellite revolving close to the Earth?

derive it.

A

v=√g R
R+h= R
gh= g

g= gravitational acceleration R= radius of Earth

R»h becuase the satellite is revoling close to the Earth that’s why height is negligible
value= 8km/s 29,000km/h

39
Q

while solving numerical questions what units should be changed?

A

km to m
g to kg

40
Q
A

Physics (9 decks)

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