Chapter 4- Mass, weight, and density Radhika Gupta

1. Mass is defined as the amount of substance in a body

1.1. Mass is a scalar quantity

1.2. Mass- SI unit: kilogram (kg)

1.3. Mass is a constant

2. Weight is defined as the gravitational force acting on an object

2.1. Weight is not a constant - i.e it varies from location to location (Earth and Moon)

2.2. The SI unit for weight is Newton (N)

2.3. Weight is a vector quantity

2.4. weight is directly proportional to mass since acceleration of a free falling object is a constant.

2.5. W=mg, where m is mass and g is gravitational field strength

3. Inertia

3.1. is defined as the reluctance of an object to change its state of rest or motion due to its mass

3.2. the tendency of an object to resist changes varies with mass.

3.2.1. The higher the mass, the higher the inertia- the larger the mass of an object the harder it will be for the object to slow down, move faster or change direction.

4. Gravitational field strength

4.1. The gravitational field strength g is the gravitational force acting per unit mass

4.2. Gravitational field is a region in which a mass experiences a force due to gravitational attraction

5. Density

5.1. The density of a substance is defined as the mass per unit volume

5.2. Substances that float on water have lower densities than water while substances that sink have higher densities than water.

5.3. SI unit- kilogram per cubic metre (kg/m3)

5.4. is calculated by mass/ volume