# MASS AND.

## Presentation on theme: "MASS AND."— Presentation transcript:

MASS AND

Remember that… Weight and Mass are not the same!
Mass is the amount of ‘’stuff’ in an object. For any given object its mass will remain the same anywhere in the universe. Weight is caused by the pull of gravity upon a mass. In most questions the weight of an object is just the force of gravity pulling it towards the centre of the Earth, make sure you refer to it as this! Although mass will remain the same, weight will change because gravitational force pulling on it will be different. Weight is a force measured in newtons by a newton meter or spring balance Mass is not a force. It is measured in kilograms with a mass balance.

Mass is not a force. It is measured in kilograms
An object has mass (say 100 kg). This makes it heavy enough to weigh 100 kg So Why Do People Say Weight instead of Mass? People often use "weight" to mean "mass", and vice versa. Because gravity is pretty much the same everywhere on Earth, we don't notice a difference. But remember .. they do not mean the same thing,  and they can have different measurements.

Why Scales Show Kilograms or Pounds
But scales show Kilograms or Pounds because that is what people understand best ... ... but it is really just an estimate of the mass above them. Scales should really show Newtons, but that might confuse people!

Grams (g) Ounces (oz) Pounds (lb)
Even people use grams, Ounces (oz) and Pounds (lb) are also used.

What objects might be grams, kilograms, pound or ounces?

Practice … Solve the different exercises using pounds or ounces.

Now….. Weight…. Weight is the force of gravity on an object. It is measured in Newtons. Weight

Calculating weight The force of gravity on one kilogram is called the gravitational field strength. It s measured in Newtons per kilogram (N/kg)

Weight (N) = mass (kg) x gravitational field strength (N/kg)
Calculating weight To calculate the weight of an object you multiply the object’s mass by the gravitational field strength wherever you are. Weight (N) = mass (kg) x gravitational field strength (N/kg)

Example The gravitational field strength on earth is around 10 N/kg. What is your weight if your mass is 45 kg? Weight (N) = mass (kg) x gravitational field strength (N/kg) Weight (N) = 45 kg x 10 N/kg Weight = 450 N

Gravity What is gravity?

Gravity Gravity is a force between ALL objects! Gravity

Gravity We only really notice the gravitational attraction to big objects! HELLO

Gravity On the moon, his weight is around 130 N. Why? 130 N

So …Mass and Weight Mass is the amount of _________ (particles) in an object. This stays the same and is measures in units of mass e.g. _______(kg) or grams (g). Objects with a _____ mass are more difficult to move. Weight the is the pull of _____ on the mass of an object. On Earth which has considerable gravity the astronaut with a mass of _____kg has a weight of ______ Newtons (N). On the moon with less gravity his weight is only ____N.

Mass and Weight Mass is the amount of matter (particles) in an object. This stays the same and is measures in units of mass e.g. kilograms (kg) or grams (g). Objects with a larger mass are more difficult to move. Weight the is the pull of gravity on the mass of an object. On Earth which has considerable gravity the astronaut with a mass of 120kg has a weight of 1200 Newtons (N). On the moon with less gravity his weight is only 200N.

SOLVING PROBLEMS… Practice by solving problems on the mathematical entertainment section.