Forces - Forces And Their Effects Flashcards
when you apply more than one force to an object, what may the object do
change shape
e.g. stretch, compress or bend
what does it mean when an object has been inelastically deformed
cannot return to original shape
what is the equation that links force to extension
force = spring constant x extension
what is spring constant measured in
N/m
what does spring constant measure
stiffness, the higher the spring constant, the stiffer
what is the limit of proportionality
the limit of how much force you can apply to an object for the extension to be proportional
on a force extension graph, what goes on what axis
y = force x = extension
how do you work out the energy stored in the elastic potential energy store using a force extension graph
its the area under the graph
what is a moment
turning effect of a force
what is the equation for a moment of a force (Nm)
force x perpendicular distance from the line of action of the force
a line at a right angle that connects the line of the force to the pivot
what happens if the clockwise moment and anticlockwise moment about a pivot are equal
it is balanced and wont move
how do levers make it easier to do work
increase distance from the pivot at which force is applied so less force is needed to get the same moment
what do gears do
transmit the rotational effect of a force from one place to another
what would happen to the moment if you transmit a force from a smaller gear to a larger one
cause a bigger moment
what is a fluid
substances which their particles can move around so they can flow
these are liquids and gasses
how would you calculate pressure at the surface of a fluid
force/ area
what 2 factors can effect the pressure of a liquid
the density. the more dense, the more particles collide
the depth. as depth increases, the number of particles above that point increase and the weight of these particles increases pressure
how would you calculate pressure at a certain depth in a column of liquid
depth x density x gravitatonal field strength
what are the 2 reasons atmospheric pressure decreases with higher altitudes
density. as altitude increases, the atmosphere becomes less dense so there are fewer air molecules that can collide with a surface
high there are fewer air molecules above a surface. so there is less weight of air above
what is upthrust and how does it work
a resultant force upwards in water
pressure increases with depth so their is a greater pressure at the bottom of the object
the upthrust is equal t the weight of the fluid that has been displaced
what about the relationship between up thrust and the object determines weather it floats or sinks
if the objects weight is more than the up thrust then it sinks. if its equal than the object floats.
