p5 forces Flashcards
what does a scalar quantity have
magnitude only e.g temperature
what does a vector quantity have
both magnitude and direction e.g velocity
what is speed
the scalar magnitude of velocity
what do forces do
push or pull on an object
contact forces
the objects are touching e.g friction, air resistance, tension
non contact forces
gravitational, electrostatic and magnetic
how are forces calculated
force (N) = mass (kg) x acceleration (m/s^2)
what measure is mass
a scalar measure of how much matter the object is made up of
what measure is weight
vector measure of how much gravity is acting on the mass
what is centre of mass
the point at which the weight of the object is considered to be acting
mass and weight are..
directly proportional
resultant force
a single force which replaces several others
when forces are balanced…
the object will remain stationary, or if it is moving, it will do so at a constant speed
what is work done
when a force acts on an object, it makes it move
rp method
- set up equipment as shown
- measure the original length if the elastic object e.g. spring
- attach a mass hanger, record the new length of the spring
- continue adding masses to the hanger in regular intervals and record the length each time
how do you find extension for the rp
spring length - original length
what graph should you have for the results of the rp
as a result of hookes law, you should have a linear graph, where gradient of the graph is equal to the spring constant
what is hookes law
the extension of an elastic object is proprtional to the force applied to the object
when is energy stored as elastic potential energy
when work is done on an elastic object e.g. spring
newtons laws of motion
the acceleration of an object is proportional to the resultant force acting on it and inversely proportional to the mass of the object
newtons third law
when two objects interact, the forces acting on one another are always equal and opposite
how is stopping distance calculated
stopping distance = thinking distance + braking distance
reaction time is affected:
- tiredness
- drugs
- alcohol
- distractions
what is reaction time
time taken for the driver to respond to a hazard
the law of conservation of mass
states that the total momentum before an event is equal to the total momentum after an event
