# 10 th, part 1, Gravitation 1 🎷

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**Link**🔗 for Test on Gravitation 1 chapter given below 👇 🎷

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🌞What are the effects of force acting on an object?

Ans:

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Ans:

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- A force can change the shape and size of the body on which the force acts.
- Can change the speed of the body,
- Force can stop a moving body,
- A force can set a body in motion,
- Force can change the direction of motion of the body,
- Force can change the speed as well as the direction of motion of the body.

🎷 What types of forces are you familiar with?

Ans:

- gravitational force
- nuclear force
- Electromagnetic force
- Frictional force
- Magnetic force,
- Spring force,
- Muscular forces.
- Tension force,
- Air resisting force.

🔱 What do you know about the gravitational force?

Ans: the gravitational force is a universal force; i.e., gravitational force acts between any two objects in the universe.

Newton’s three laws of motion can never be forgotten in life.

🥁 Newton’s first law of motion:-

An object continues to remain at rest or in a state of uniform motion along a straight line unless an external unbalanced force acts on it.

An object continues to remain at rest or in a state of uniform motion along a straight line unless an external unbalanced force acts on it.

🎇Newton’s second law of motion:-

The rate of change of momentum is proportional to the applied force and the change of momentum occurs in the direction of the force.

The rate of change of momentum is proportional to the applied force and the change of momentum occurs in the direction of the force.

🥭 Newton’s third law of motion:-

Every action force has an equal and opposite reaction force which acts simultaneously.

Every action force has an equal and opposite reaction force which acts simultaneously.

☘️ Kepler’s first law of planetary motion

The orbit of a planet is an ellipse with the sun at one of the foci.

The orbit of a planet is an ellipse with the sun at one of the foci.

Kepler’s second law of planetary motion:-

The line joining the planet and the sun sweeps equal areas in equal intervals of time.

The line joining the planet and the sun sweeps equal areas in equal intervals of time.

Kepler’s third law of planetary motion:–

The square of the period of revolution (T^2) of a planet around the sun is directly proportional to the cube of the main distance (r^3) of the planet from the sun.

✍️ Newton’s universal law of gravitation:-

Every object in the universe attracts every other object with a definite force this force is directive proportional to the product of the masses of the two objects and inversely proportional to the square of the distance between them.

F=Gm1m2/r^2

G-constant of proportionally, universal gravitational constant.

The value of G is 6.673 × 10^ -11Nm^2 kg^-2

Acceleration due to gravitational force on the earth

g = GM/ r^2

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**Mass**- The amount of matter present in a body is called its mass.
- The SI unit of masses Kg.
- Mass is a scalar quantity.
- Mass is measured by equilibrium balance.
- The mass of a body does not change from place to place.
- Mass can never be zero.

🦢 **Weight**

- The force of gravity acting on a body is called its weight.
- The SI unit of weight is N.
- Weight is a Vector quantity.
- Weight is measured by spring balance.
- Weight can change from please replace.
- Weight can be zero in space and at the center of the Earth.

We can write

**difference between mass and weight**with the help of account 6 points respectively.⭕ **The weight of 1 kg mass is = 9.8 N.**

😎

High and low tides are offered regularly in the sea. The level of water in the sea changes because of the gravitational force exerted by the moon. Water directly under the moon gets spooled towards the moon and the level of water there goes up causing high tide at that place.

At two places on the earth at 90 ° from the place of high tide, the level of water is minimal, and low tides occur there.

**Tides**High and low tides are offered regularly in the sea. The level of water in the sea changes because of the gravitational force exerted by the moon. Water directly under the moon gets spooled towards the moon and the level of water there goes up causing high tide at that place.

At two places on the earth at 90 ° from the place of high tide, the level of water is minimal, and low tides occur there.

🎻

**Free fall**Whenever an object moves under the influence of gravity alone, it is said to be fallen freely.

Free fall is possible only in vacuum.

**Some important points from this lesson.**

- The weight of a body is maximum to a poles.
- The value of the acceleration due to gravity increases as we move from the equator to the pole.
- If the earth shrinks to half of its radius, it’s mass remaining the same, the weight of an object on the earth will become four times.
- The CGS unit of weight is the dyne.
- According to kepler’s second law the line joining the planet and the sun sweeps equal areas in equal interval of time.
- As we go about the Earth’s surface the value of g decrease./
- The value of g decreases with altitude.
- The value of G is the same throughout the universe.
- The weight of a body is maximum at the poles.
- At the center of the earth the value of the acceleration due to gravity becomes zero.
- g has maximum value at the poles.

**❤️ A Link 🔗 for Test on Gravitation 1 chapter given below 👇 🎷**

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