Advertisements
Advertisements
Question
Molecules in air in the atmosphere are attracted by gravitational force of the earth. Explain why all of them do not fall into the earth just like an apple falling from a tree.
Advertisements
Solution
Air molecules in the atmosphere are attracted by the gravitational force of the earth but they do not fall into the earth due to the reason that the molecules in air have some random motion due to temperature, so their resultant motion is not exactly the vertically downward direction.
But in the case of apples, only vertical motion dominates because of being heavier than air molecules. But due to gravity, the density of air is more near to the earth than the density as we go up.
APPEARS IN
RELATED QUESTIONS
How does the force of gravitation between two objects change when the distance between them is reduced to half?
What happens to the force between two objects, if the distance between the objects is doubled and tripled?
What is the importance of the universal law of gravitation?
A rocket is fired from the earth towards the sun. At what distance from the earth’s centre is the gravitational force on the rocket zero? Mass of the sun = 2 ×1030 kg, mass of the earth = 6 × 1024 kg. Neglect the effect of other planets etc. (orbital radius = 1.5 × 1011 m).
Can we apply Newton’s third law to the gravitational force ? Explain your answer.
A body is suspended from a spring balance kept in a satellite. The reading of the balance is W1 when the satellite goes in an orbit of radius R and is W2 when it goes in an orbit of radius 2 −R.
A solid sphere of mass m and radius r is placed inside a hollow thin spherical shell of mass M and radius R as shown in the following figure . A particle of mass m' is placed on the line joining the two centres at a distance x from the point of contact of the sphere and the shell. Find the magnitude of the resultant gravitational force on this particle due to the sphere and the shell if (a) r < x < 2r, (b) 2r < x < 2R and (c) x > 2R.
State whether the gravitational force between two masses is attractive or repulsive ?
How will the force of gravitation between two objects change if the distance between them is:
Made four times
Why don't you feel the force of attraction between your friend sitting close to you and yourself?
A ball is thrown up with a speed of 4.9 ms-1.
Calculate the maximum height it would gain before it begins to fall.
What does a force do in the following case?
You pull the skin of your arm
Gravity is another kind of ________. It exerts all through the ________. The Sun's gravity keeps the ___________ in their orbits. Gravity can only be felt with very large ________.
State Newton's law of gravitation. What is the difference between:
Gravity and gravitation
Particles of masses 2M, m and M are respectively at points A, B and C with AB = ½ (BC). m is much-much smaller than M and at time t = 0, they are all at rest (Figure). At subsequent times before any collision takes place ______.
Give scientific reasons for the following:
Newton's gravitational law is the universal law of gravitation.
Complete the chart below.
| F(N) | M1(kg) | M2(kg) | D(m) |
| (a) | 50 | 84 | 02 |
| 16 × 109 | 1.63 × 1022 | (b) | 34 |
Find the gravitational force of attraction between the ring and sphere as shown in the diagram, where the plane of the ring is perpendicular to the line joining the centres. If `sqrt8` R is the distance between the centres of a ring (of mass 'm')and a sphere (mass 'M') where both have equal radius 'R'.
The acceleration of the Moon towards the Earth is approximately ______.
