P5 Flashcards
What is a vector quantity?
Have a magnitude and a direction
Examples of vector quantities?
Force Velocity Displacement Acceleration Momentum
What is a scalar quantity?
Only have a magnitude , no direction
Examples of scalar quantities
Speed Distance Time Temperature Mass
How are vectors usually represented?
Using an arrow, the length of the arrow shows the magnitude and the direction shows the direction of the quantity
What is a force?
A push or a pull on an object that is caused by interacting with something
What do all forces have to be?
Contact or non contact
What is a contact force?
Objects are physically touching
What is a non contact force?
Two objects dont need to be touching
Examples of contact forced?
Friction
Air resistance
Tension
Normal contact force
Examples of non contact forces?
Magnetic force
Gravitational force
Electrostatic force
What happens when two objects interact?
There is a force produced on both objects. The force is equal and opposite
Two important effects of gravity?
- on the surface of a planet, it pulls things towards the ground
- gives everything a weight
What is the mass of an object?
The amount of stuff within an object. The mass does not change .
What is the weight of an object?
Force acting on an object due to gravity (pull of the gravitational force on an object). It is caused by a gravitational field around the earth.
How does gravitational field strength vary?
Varies with location. Its stronger the closer you are to the mass causing the field , and stronger for larger massee.
What does the weight of an object depend on?
Strength of the gravitational field at the location of the object. The weight changes with a change of location.
What is weight measured in?
Newtons
What is gravitational field strength measured in?
Newtons per kilogram
What is the centre of mass of an object?
Single point on an object where the force (weight ) is acting. At the point you assume the whole mass is concentrated. For an object that has the same density throughout the shape , the point will be at the exact centre.
Is mass a force?
No
How is weight measured?
Using a calibrated spring balance(newtonmetre
How to work out the weight of an object?
Mass x gravitational field strength
How are mass and weight related?
They are directly proportional.