## Gravitation Notes And NCERT Solutions Of Class 9th Chapter-10 Science.

• March 15, 2021

## Frequently Asked Questions on chapter 10 Gravitation

State the universal law of gravitation.

The universal law of gravitation states that every object in the universe attracts every other object with a force called the gravitational force. The force acting between two objects is directly proportional to the product of their masses and inversely proportional to the square of the distance between their centers.

What do you mean by free fall?

Earth’s gravity attracts each object to its center. When an object is dropped from a certain height, under the influence of gravitational force it begins to fall to the surface of Earth. Such an object movement is called free fall.

Why is the weight of an object on the moon 1/6th its weight on the earth?

The moon’s mass is 1/100 times and 1/4 times the earth’s radius. As a result, when compared to earth, the gravitational attraction on the moon is about one sixth. Thus, an object’s weight on the moon is 1/6th its earth weight.

What do you mean by buoyancy?

The upward force possessed by a liquid on an object that’s immersed in it is referred to as buoyancy.

You find your mass to be 42 kg on a weighing machine. Is your mass more or less than 42 kg?

When weighing our body, it is acting by an upward force. The buoyant force is this upward force. As a result, the body is pushed up slightly, resulting in the weighing machine showing less reading than the actual value.

Gravitational force acts on all objects in proportion to their masses. Why then, a heavy object does not fall faster than a light object?

All objects fall on the bottom with constant acceleration called acceleration thanks to gravity (g). It’s constant and therefore the price of ‘g’ doesn’t depend on the mass of an associate object. So serious objects don’t fall quicker than light-weight objects provided there’s no air resistance.

What do we call the gravitational force between the earth and an object?

Gravitational force is known as the object’s weight between the earth and an object.

Why will a sheet of paper fall slower than one that is crumpled into a ball?

A sheet of paper has a lot of area as compared to a crumpled paper ball. A sheet of paper must face a lot of air resistance. As a result, a sheet of paper falls slower than the crumpled ball.

In what direction does the buoyant force on an object immersed in a liquid act?

The buoyant force on an object that is immersed in a liquid will be in a vertically upward direction.

Why a block of plastic does released under water come up to the surface of the water?

The density of plastic is a smaller amount than that of water, therefore the force of buoyancy on the plastic block are going to be bigger than a load of plastic block displaced. Hence, the acceleration of the plastic block is going to be in an upward direction and comes up to the surface of the water.