Understanding Gravity

Card 1: Gravitational Field

Gravitational Field

A gravitational field as a region in which an object experiences a force due to gravitational attraction

Card 2: Gravitational Field Strength

Gravitational Field Strength

The gravitational field strength at a point in the gravitational field is the gravitational force acting on a mass of 1 kg placed at that point.

Unit: N/kg

Symbol: g

Card 3: Formula of Gravitational Field Strength

Gravitational Field Strength Formula

Card 4: Gravitational Acceleration

Gravitational Acceleration

The gravitational acceleration is the acceleration of an object due to the pull of the gravitational force.

Unit: ms-2

Symbol: g

Important notes:

  • Gravitational acceleration does not depend on the mass of the moving object.
  • The magnitude of gravitational acceleration is taken to be 10ms-2.
Card 5: Comparing gravitational field strength and gravitational acceleration

Gravitational Field Strength vs. Gravitational Acceleration

  • Both the gravitational field strength and gravitational acceleration have the symbol, g and the same value (10ms-2) on the surface of the earth.
  • When considering a body falling freely, the g is the gravitational acceleration.
  • When considering objects at rest, g is the Earth’s gravitational field strength acting on it.
Card 6: What is weight?

Weight

The weight of an object is defined as the gravitational force acting on the object.

Unit: Newton (N)

Card 7: Differences between Weight and Mass

Differences between Weight and Mass

Weight
Mass
Depends on the gravitational field strength Independent from the gravitational field strength
Vector quantity Scalar Quantity
Unit Newton (N) Unit: Kilogram (kg)
Card 8: What is free falling?

Free Falling

Free falling is a motion under force of gravity as the only force acting on the moving object.

Practically, free falling can only take place in vacuum.

Card 9: Free falling case 1 - Falling from high place

Falling from high place

freefall.png

Acceleration = 10ms-2
Initial velocity = 0
Displacement = high of the location

Card 10: Free falling case 2 - Launching object upward

Launching object upward

freefall2.png

Acceleration = -10ms-2
Velocity at maximum height = 0

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