Key Concepts
- The Earth’s gravity
- Consequences of the Earth’s gravity
Introduction:
It is known that an object may start or stop its motion and slow down or speed up its motion when a force is applied to it. A force is always responsible for the motion of a body. Therefore, it can be concluded that a force is responsible for the falling motion of bodies as well. This force that pulls objects towards the Earth is the Earth’s gravity. In this section, we will be looking at the Earth’s gravity in detail.
Explanation:
The Earth’s gravity:
A ball, when thrown upwards, no matter how hard it is thrown, moves to some distance and then falls back to the ground. This happens due to the Earth’s gravity. Gravity is a force applied by our planet Earth on the objects on and around it. The Earth’s gravity is a force that pulls objects towards its center. Any object that lies on the Earth or near it is pulled towards itself because of gravity.
Examples:
- A juggler throws many balls upwards. However, gravity pulls all of them down.
- If you suddenly drop your pencil while holding it, the Earth’s gravity pulls it down to the floor.
- Dried leaves fall off the trees as the Earth’s gravity pulls them down towards the ground.
- A tumbler jumps while performing a somersault in the air, knowing that he would be brought back to the ground by the Earth’s gravity.
- The trees remain fixed in their places because of the Earth’s gravity.
- The gravity keeps a table on the ground and the stationery like books on the table in their respective places.
- All humans and animals are able to balance while walking and running because of gravity.
From all these instances, we can conclude that the Earth’s gravity acts on and pulls the objects lying close to the ground and lying on the ground towards itself.
Consequences of the Earth’s gravity:
Gravity and Weight:
The Earth’s gravity gives us the weight. The more massive an object is, the more is the gravitational pull of the Earth on it, and hence, the more would be its weight.
The weight of the elephant is much more than its calf. This is because the elephant is more massive than her calf, and hence, the gravitational pull is more for the elephant.
Weightlessness:
If the Earth’s gravity disappears, everything lying on the ground will start floating, including people, animals and things. This is because they become weightless in the absence of gravity.
The weightlessness is experienced by the people who travel in a space shuttle and astronauts. Astronauts float randomly all around.
Questions and answers:
- Why does a ball dropped from the top of a building moves towards the ground?
Answer:
- A ball dropped from the top of a building moves towards the ground as it is pulled by the Earth’s gravity towards the center of the Earth.
- Arrange the following objects in the descending order of their weights.
- A bed tray
- A table
- An eraser
- A laptop
Summary
- A ball, when thrown upwards, no matter how hard it is thrown, moves to some distance and then falls back to the ground.
- This happens because of a force named gravity.
- Gravity is a force applied by our planet Earth on the objects on and around it.
- The Earth’s gravity is a force that pulls objects towards its center.
- Any object, that lies on the Earth or near it is pulled towards itself because of gravity.
- The Earth’s gravity acts on the objects both in contact and not in contact with it.
- The Earth’s gravity gives us the weight. The more massive an object is, the more is the gravitational pull of the Earth on it, the more would be its weight.
- If the Earth’s gravity disappears everything lying on the ground would start floating including people, animals and things. This is because they become weightless in the absence of gravity.
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