Gravitational Force

Gravity is a force that attracts two objects with mass toward each other. The force of gravity is what holds us to the ground and keeps the planets in orbit around the sun. The strength of the gravitational force between two objects depends on two things: the mass of the objects and the distance between them. The more massive an object is, the stronger its gravitational pull. The farther apart two objects are, the weaker the gravitational force between them.

For example, the force of gravity between the Earth and the moon is what keeps the moon in orbit around the Earth. Similarly, the force of gravity between the earth and the sun is what keeps the Earth in orbit around the sun. The force of gravity is what makes things fall to the ground when we drop them. This is because the force of gravity is pulling the object toward the center of the earth.

The force of gravity is a fundamental force of nature and it can’t be turned off or blocked, but it can be overpowered by other forces like friction or air resistance.

The gravitational force plays an essential role in our daily life and in the universe, it holds planets and stars in place, it controls the movement of celestial bodies and it governs the behavior of the universe on a large scale.

It describes the strength of the gravitational force between two objects with mass. 

The equation shows that the force of gravity is directly proportional to the product of the masses of the two objects and inversely proportional to the square of the distance between them.

An example of this equation would be calculating the gravitational force between the Earth and the Moon. The Earth has a mass of 5.972 x 10^24 kg and the Moon has a mass of 7.347 x 10^22 kg. The distance between the centers of the Earth and the Moon is about 384,400 km. Using these values in the equation:

F = (6.67 x 10^-11 N*(m^2)/(kg^2)) * ((5.972 x 10^24 kg) * (7.347 x 10^22 kg)) / (384,400 x 10^3 m)^2

The equation of motion for gravitation, F = m * a, is used to describe the motion of an object subject to a gravitational force. It is the second law of motion. This equation relates the force of gravity acting on an object, its mass, and its acceleration.

An example of this equation would be calculating the weight of an object on the surface of the Earth. The acceleration due to gravity on the surface of the Earth is 9.8 m/s^2. If the mass of an object is 10 kg, then the weight of the object is:

F = 10 kg * 9.8 m/s^2 = 98 N

The equation for gravitational potential energy, U = – G * (m1 * m2) / r, describes the potential energy stored in an object due to its position in a gravitational field. The equation shows that the potential energy is directly proportional to the product of the masses of the two objects, inversely proportional to the distance between them, and has a negative sign because it is a conservative force.

An example of this equation would be calculating the gravitational potential energy of an object at a certain height above the Earth. The mass of the object is 10 kg and its height above the Earth’s surface is 100 meters. Using these values in the equation:

U = – (6.67 x 10^-11 N*(m^2)/(kg^2)) * (10 kg) * (5.972 x 10^24 kg) / (100m)

It’s important to note that the universal gravitation equation applies to any two objects with mass, not only to the earth and the object, it applies to all objects in the universe, including planets, stars, galaxies, and even black holes.

Quick Check 

Q1. Calculate the force of gravity acting on an object weighing 9.8 kg. 

Q2. How gravitational potential energy varies with an increase in distance between 2 objects? 

Q3. Justify the statement – Gravitational force can’t be blocked but can be overpowered by other forces.

Examples of Gravity

There are many examples of gravity in our everyday life and in the natural world. Here are a few:

• The force that keeps us and all objects on the surface of the Earth is gravity. It is what makes things fall to the ground when we drop them.

• The orbits of planets, moons and other celestial bodies are determined by the force of gravity. For example, the force of gravity between the Earth and the Moon is what keeps the Moon in orbit around the Earth. Similarly, the force of gravity between the Earth and the Sun is what keeps the Earth in orbit around the Sun.

• The tides in the ocean are caused by the gravitational pull of the Moon and the Sun on the Earth’s water.

• The gravitational pull of a black hole is so strong that it can bend light and even trap light, this is called the event horizon.

• The gravitational pull of a star is responsible for holding the planets in their orbits and preventing them from drifting away into space.

• The gravitational pull between two galaxies can cause them to collide and merge together over time.

• The gravitational pull of a massive object can cause the surrounding space-time to warp and bend, this is called gravitational lensing.

• The force of gravity acts between all objects with mass, not only on Earth but also on every object in the universe.

These are just a few examples, but gravity plays a role in many other natural phenomena and in the behavior of the universe on a large scale.

Gravitational Force FAQs

Grade 7 Science Worksheets

• Elements and Compounds
• Solar Energy
• Photosynthesis
• Electricity and Magnetism
• Law of conservation of energy
• Periodic table
• Properties of Matter
• Waves
• Energy Resources 
• Weather and Climate
• Immune, Circulatory and Digestive Systems
• Organs in Multi-cellular Organism
• Sedimentary, Igneous, and Metamorphic Rocks
• Structure of the Earth
• Law of Conservation of Mass
• Physical and Chemical Changes
• Scientific Method
• Human Digestive System
• Environmental Science
• Renewable and Non-renewable energy Resources
• Characteristics of Living Organisms
• Life Science
• Earth and Space Science
• Solar Eclipse
• Heat Technology
• Newton’s Laws of Motions
• Physical Science
• Tools, Measurement and SI Units
• Earth Atmosphere
• Interactions of Living things
• The Earth Ecosystem
• Organelles in Plant and Animal cells
• Layers of the Earth
• Cycles in Nature

Grade 7 Math Worksheets

• Fractions
• Linear equations word problems
• Statistics
• Properties of Parallel Line 
• Finding slope from an equation
• Identifying Quadrilaterals
• Percent Change
• Properties of addition and multiplication
• Pythagorean Theorem
• Solving two step inequalities
• Symmetry
• Fractions to Decimals (New)
• Whole Number Exponents with Integer Bases (New)
• Adding and Subtracting Fractions (New)
• Integer Addition and Subtraction (New)
• Dividing Mixed Numbers (New)
• Basics of Coordinate Geometry (New)