Forces pt1 (Scalar, contact, Gravity, Work done, Elasticity, moment) Flashcards
What is a force?
A force is a push or pull that acts on an object due to the interaction with another object.
what is a scalar quantity?
magnitude only
what is a vector quantity?
magnitude and direction
What is are contact forces?
when the objects are physically touching
What is a non-contact forces?
when the objects are physically separated.
examples of non-contact forces (3)
gravitational force electrostatic force magnetic force
What type of quantity is force?
vector
Examples of contact forces?
friction, air resistance, tension and normal contact force.
what is gravity?
a force of attraction between all masses
What is the gravitational force close to Earth caused by?
the gravitational field around theEarth.
what is mass?
the amount of matter an object contains - this is constant
what is the weight?
the force acting on an object due to gravity
what is the equation for gravitational field strength, mass and weight?
weight = mass x gravitational field strength
What is the connection between weight and mass
(proportion)
they are directly proportional
what is work done?
when a force causes an object to move
what are the two units for work done
joule and newton metres
what is the equation for force, work done and distance?
work done = force x distance
what happens when work is done?
energy transfers take place within the system
the extension of an elastic object is ___________ to the force applied , provided that the ___________ is not exceeded
directly proportional
limit of proportionality
what must happen to change the shape of an object?
more than one force must be applied
what does elastically deformed mean?
when an object returns to its original shape after the forces are removed
what does inelastically deformed mean?
when an object does not return to its original shape
what happens when the limit of proportionality for the extension of an elastic object and applied force has been exceeded? (3)
- doubling the force will no longer exactly double the extension - the relationship becomes non-linear - a force-extension graph will stop being a straight line
what is the equation for , extension , force, and spring constant
force= spring constant x extension
what is spring constant?
it indicates how easy it is to stretch or compress a spring- the higher the spring constant, the stiffer the spring.
when is the work done on the spring and the elastic potential energy stored not equal
when the spring is inelastically deformed
what is the moment of a force?
the turning effect of a force
what is the equation for distance, moment and force?
moment = force x distance
What is the distance in terms of the moment?
the perpendicular distance from the pivot to the line of action of the force, in metres, m.
If an object is balance…..
the total clockwise moment about the pivot = the total anticlockwise moment about that pivot
leavers and gears can be used to…
- transmit the rotational effects of forces - magnify either the size of the applied force or the distance the force moves over
what do levers do?
- increase the distance from the pivot at which the force is applied
- less force is needed to get the same moment so its easier to do work
what do gears do and how do they work?
they are used to transmit the rotational effect of a force from one place to another
- their teeth interlock so the one turning causes another to turn in the opposite direction
larger gears …
-cause bigger moments - turn slower
equation for distance, speed and time
distance = speed x time
