Mass, Weight and Centre of Gravity

Mass

The amount of matter un an object

What are the kinematic implications of a high mass

Greater resistance to a change in velocity

Weight

The force experienced by a mass due to gravitational field strength

Weight equation

W = mg

Centre of gravity

The single point that you can consider the whole weight to act through- whatever its orientation

How to find the centre of gravity for a regular object

The point at which the lines of symmetry cross

How to find the centre of gravity of an irregular object

1- Hang the object on a string with a plumb bob with a clip at a point

2- Draw a vertical line downwards from the point of suspension

3- Hang the object from a different point and repeat

4- The centre of gravity is halfway between the thickness of the object at the point of intersection between the two lines

Why is a plumb bob used in the centre of gravity experiment

To make sure the line is exactly vertical

What is more stable- a higher or lower centre of gravity

Lower

What is more stable- a wider or shorter base area

Wider

Explain why a wider base area makes an object more stable

The vertical line drawn downwards from the centre of gravity is more likely to fall inside the base area

Explain why a lower centre of gravity makes an object more stable

The object will need to be tilted at a greater angle before it falls over

How can you tell if an object will fall over

A line drawn from the centre of the gravity will fall outside of the base area

Plumb bob

A weight on a string