when something has a magnitude but no direction
vector means when something has both a magnitude and direction
speed, mass, distance
velocity, force, weight
distance is the length of a path between two points
displacement is the direction from the starting point and the length of a straight line from the starting point to the ending point
when two objects interact with each other, they exert equal and opposite forces on each other.
the centre of mass of an object is the point at which its mass can be thought of as being concentrated
the centre of mass directly below the point where it is suspended
resultant force is the result of all forces acting (overall force)
if an object is not movingand has zero resultant force it stays not moving. whereas if an object is moving and has zero resultant force it means it is moving at a steady or constant speed.
weight=mass x gravitational field strength (w=m x g)
the weight of an object is the force of gravity that acts on its mass
gravitational field strength is an accelleration due to the strength of the gravitational field
work in physics is the amoubt of energy transformed (changed) when a force moves (in the direction of the force)
work done = force x distance
joules = newtons x metres
power = work done / time
watts = joules / seconds
hookes law states that the force applied to an elsastic object (spring) is directly proportional to the extension it causes
the ability to be deformed by forces but still return to its original shape and size
when an object is deformed by forces but does not return to its original shape and size when forces are removed
extension is the distance an object has been stretched or extended by, NOT how long it is. for example an unstretched spring is 2cm and is stretched so it is now 10cm ling so the extension is 8cm long
force = spring constant x extension
kinetic energy = 1/2 x mass x velocity ^2
density = mass x volume
gravitational potential energy = gravitational field strength x height x mass
elastic potential energy is the energy being stored by an elastic object when it is being stretched or squashed
when an object is being stretched, the more Ee it has but if an object is not stretched then it is not storing any elastic potential energy
power= energy / time
contact forces are forces that occur due to objects being in contact with each other. whereas non contact forces don't need to be in contact with another object.
energy cannot be created or destroyed, only transferred
friction, air resistance, push, pull
gravity, magnetic, electrostatic