P5 - Weight,Mass And Gravity

Question 1

What is gravitational force?

Answer 1

The force of attraction between masses

Question 2

What does gravity do

Answer 2

Attract all masses, but you only notice it when one of the masses is really big eg. A planet

( Anything near a planet is attracted to it very strongly)

Question 3

What are the two effects of gravitational force?

Answer 3

1 On the surface of a planet, it makes all things fall towards the ground
2) It gives everything a weight

Question 4

NOTE:

Answer 4

Weight and mass are not the same

Question 5

What is mass?

Answer 5

Mass is just the amount of matter (stuff) in an object. For any given object this will have the same value anywhere in the universe.

Question 6

What is weight?

Answer 6

Weight is the force acting on an object due to gravity (the pull of the gravitational force on the object).

(Close to Earth, this force is caused by the gravitational field around the Earth)

Question 7

Why does the gravitation field’s strength vary?

Answer 7

Gravitational field varies with location. It’s stronger the closer you are to the mass causing the field, and stronger for larger masses.

Question 8

What does the weight of an object depend on?

Answer 8

The weight of an object depends on the strength of the gravitational field at the location of the object. This means that the weight of an object changes with its location

( For example, an object has the same mass whether it’s on Earth or on the Moon - but its weight will be different. A 1 kg mass will weigh less on the Moon (about 1.6 N) than it does on Earth (about 9.8 N), simply because the gravitational field strength on the surface of the Moon is less.)

Question 9

What does weight measure in?

Answer 9

Newtons

Question 10

What is the centre of mass?

Answer 10

A point at which you assume the whole mass is concentrated

( For a uniform object (one that’s the same density,throughout and is a regular shape), this will be at the centre of the object.)

Question 11

How is weight measured?

Answer 11

Using a calibrated spring balance ( or newtonmeter)

Question 12

How is mass measured?

Answer 12

It’s measured in kilograms with a mass balance (a pair of balancing scales).

Note : Mass is not a force

Question 13

What is a similarity of mass and weight?

Answer 13

They are directly proportional to each other

( This means Increasing the mass of an object increases its weight. If you double the mass, the weight doubles too)

Question 14

State the Equation to calculate weight

Answer 14

Weight (N) = Mass (kg) × Gravitational Field Strength (N/kg)

Question 15

What is the gravitational field strength of:

1) The Earth
2) The Moon

Answer 15

The Earth = 9.8 N/kg
The Moon = 1.6 N/kg