Topic 5 - Forces Flashcards
What effect does gravity have
-On the surface of a planet it makes all things fall towards the ground
-It gives everything a weight
What is the mass of something
The amount of matter in an object
What is the weight of something
-The force acting on an object due to gravity (the pull of the gravitational forces on the objects)
-On earth this is caused by the gravitational field around the earth
How does the location of gravitational field vary its strength
It’s stronger the closer you are to the mass causing the field, and stronger for larger masses.
Why does the weight of an object depend on its location
Because the weight of an object depends on the strength of the gravitational field at the location of the object.
Give an example of an object that weighs differently on the earth and on the moon
A 1kg weight will weigh around 1.6N on the moon but 9.8N on earth as the gravitational field strength on the moon is less.
What is weight measured in.
Where does the weight of an object act
It acts from a single point on the object, called it’s centre of mass
How is weight measured
Using a calibrated spring balance or newtonmeter
What is mass measured by and what is its units
It’s measured in kilograms with a mass balance
What is the equation that links weight, mass and gravitational field strength
Weight (N) = Mass (kg) x Gravitational Field Strength (N/kg)
What is the link between weight and mass
They are directly proportional
How do you write that weight and mass are directly proportional
W ∝ M
What happens when a force moves an object through a distance
Energy is transferred and work is done on the object
What must there be to make something move
A force must be applied and the thing applying the forces needs a source of energy