# Concept Map

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# Teaching Outlines

## Concept #1 - Nature of Gravitational Force

### Learning objectives

1. Inertial and Gravitational Property of Mass
2. Idea of a force field and that forces can act at a distance. The distance over which the effect of a force can be felt is called its field.
3. Gravitational force acts over a distance through a field and is one of the four fundamental forces
4. Gravitational force is a very small force

### Notes for teachers

These are short notes that the teacher wants to share about the concept, any locally relevant information, specific instructions on what kind of methodology used and common misconceptions/mistakes.

• Mass has two aspects – inertial and gravitational. We are familiar with mass; it is an intrinsic property of matter. An intrinsic property is something that cannot be separated from the object. The mass of an object can be understood in terms of its gravitational aspect and inertial aspect. The intrinsic property of matter which makes it resist change is what we have called as mass. But this same mass possesses another property – the ability to “attract” mass. This we call the gravitational aspect. The gravitational aspect of the mass is responsible for the attractive force between two masses. The gravitational aspect is what makes masses interact with one another.
• Gravitation is a fundamental force. Gravitational force, or gravity, is the force by which physical bodies attract each other with a force directly proportional to their mass and inversely proportional to the square of the distance between them. This is one of the four fundamental forces in nature. Gravity is the force which makes masses interact with one another. Gravitational force is mutually attractive. Another fundamental force is the electromagnetic force, due to another intrinsic property of matter – charge. These forces are due to charges possessed by an object and their movement.
• Strong and weak nuclear forces are other fundamental forces that act within the nucleus of an atom, holding it together. These forces however act only at the subatomic level. Above the atomic level, gravitational and electromagnetic forces can satisfactorily explain all events.

### Activity No #

• Estimated Time
• Materials/ Resources needed
• Prerequisites/Instructions, if any
• Multimedia resources
• Process (How to do the activity)
• Developmental Questions (What discussion questions)
• Evaluation (Questions for assessment of the child)
• Question Corner

### Activity No #

• Estimated Time
• Materials/ Resources needed
• Prerequisites/Instructions, if any
• Multimedia resources
• Process (How to do the activity)
• Developmental Questions (What discussion questions)
• Evaluation (Questions for assessment of the child)
• Question Corner

## Concept #2 - Newton's law of universal gravitation

Newton's law of universal gravitation states that every particle in the universe attracts every other particle with a force that is proportional to the product of their masses and inversely proportional to the square of the distance between them. This force acts along the line joining the two particles. Separately it was shown that large spherically symmetrical masses attract and are attracted as if all their mass were concentrated at their centres.

For non-symmetric objects, the masses will be concentrated a the centre of mass and the distance between these centres is what will be taken as the distance

F = G m1m2 / r2

• F is the force between the masses,
• m1 is the first mass,
• m2 is the second mass,
• G is the gravitational constant
• r is the distance between the masses

In SI units, Force, F is measured in newtons (N), masses m1 and m2 are measured in kilograms (kg), and the distance between the masses is measured in metres.

### Notes for teachers

These are short notes that the teacher wants to share about the concept, any locally relevant information, specific instructions on what kind of methodology used and common misconceptions/mistakes.

### Activity No #

• Estimated Time
• Materials/ Resources needed
• Prerequisites/Instructions, if any
• Multimedia resources
• Process (How to do the activity)
• Developmental Questions (What discussion questions)
• Evaluation (Questions for assessment of the child)
• Question Corner

### Activity No #

• Estimated Time
• Materials/ Resources needed
• Prerequisites/Instructions, if any
• Multimedia resources