P5 Flashcards
What is a vector quanity
A quanity that has both magnitude and direction
What is a scalar quanity
A quantity that has only magnitude and NO direction
How are vectors usually represented
By an arrow - the length of the arrow shows the magnitude,and the direction of the arrow shows the direction of the quantity
State examples of a vector quantity
- Force
- Velocity
- Displacement
- Acceleration
- Momentum
State examples of scalar quanitites
- Speed
- Distance
- Mass
- Temperature
- Time
What is a force?
A force is a push or pull that acts on an object due to the interaction with another object. All forces between forces are either contact or non contact forces
What is a contact force?
When two objects touch each other in order for a force to act,it is a contact force
What is a non-contact force?
If the objects do not need to be touching for a force to act,it is a non-contact force
State examples of contact forces
- Friction
- Air resistance
- Tension
- Normal contact force
State examples of a non-contact force
- Magnetic force
- Gravitational force
- Electrostatic force
Is force a scalar or vector quantity?
Vector quanity
What is an interaction pair?
A pair of forces that are equal and opposite and act on two interacting objects
(This is basically newtons third law)
A tennis ball is dropped from a height.Name one contact and one non-contact force
Contact force - Air resistance
Non-contact force - Gravitational force
(The air resistance is going up whilst the gravitational force is going down)
Note:
AQA says that students should be able to describe the interaction between pairs of objects which produce a force on each object. The forces are to be represented as vectors
What is weight?
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)
What does the weight of an object depend on?
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.)
What does weight measure in?
Newtons
State the equation to find the weight of an object
Weight(N) = Mass(kg) x Gravitational field strength(N/kg)
W = mg
What is the centre of mass?
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.)
What is a similarity of mass and weight?
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)
How is weight measured?
Using a calibrated spring balance ( or newtonmeter)
How is mass measured?
It’s measured in kilograms with a mass balance (a pair of balancing scales).
Note : Mass is not a force
What is the resultant force?
The overall Force on a Point or Object
Note:
AQA says that students should be able to calculate the resultant of two forces that act in a straight line