Mechanical Systems Flashcards
simple machines (name 5)
inclined plane, gears, wheel and axle, pulley, levers
inclined plane
a ramp or slope for reducing
the force needed to lift something
gears
a rotating wheel-like device with teeth around its rim
wheel and axle
a machine consisting of two turning objects
attached to each other at their centres.
One object causes the other to turn.
hydraulics
the study of pressure in liquids
pneumatics
the study of pressure in gases
pulley
a wheel with a grooved rim to guide a rope or
chain that runs along the groove;
used to transmit or change direction of force
Lever
a machine consisting of a bar that is free to rotate around a fixed point, changing the amount of force that must be exerted to move an object
how do machines impact people and society
..
What relationship is there between the
piston and the wheel of the device?
the piston transmits kinetic energy to the wheel
What is a subsystem?
a simple machine that is part of a larger system
screw
wedge
..
mechanical advantage formula (force)
mechanical advantage =
Load force
———————
Effort force
or
MA=FL/FE
mechanical advantage formula (for levers)
MA levers =
Length of force arm
———————————
Length of load arm
mechanical advantage formula (for wheel and axle)
MA wheel and axle =
Radius of force arm
———————————
Radius of load arm
fulcrum
the point of a lever that DOES NOT move
effort arm
in a lever,
the distance between the fulcrum and the effort force
load arm
in a lever,
the distance from the load to the fulcrum
class ONE lever
a lever in which the fulcrum is
between the effort and the load
(teetertotter)
class TWO lever
a lever in which the load is between the
fulcrum and the effort
(bottle opener)
class THREE lever
a lever in which the effort is applied between
the fulcrum and the load
(tweezers)
effort force
the force supplied to any
machine to produce an action
load
the weight of an object that is moved or lifted by a machine, or the resistance to movement that a machine must overcome
work
the transfer of energy through motion
WORK = force x distance
joules
a unit used to measure energy or work;
1J = a force of 1N moving through 1m
work input
work output
..
mechanical advantage
the ratio of the force produced by a machine or system (the load) to the force applied to the machine or system (the effort force)
speed
the rate of motion,
or the rate at which an object changes its position
force
a push or pull on anything that causes
a change in the motion of an object
The unit for measuring force is the NEWTON
area
the amount of surface;
measured in square unit such as cm2
pressure
the force acting perpendicular
to a certain surface area
Pascal’s law
a law stating that when pressure is exerted on one part of a fluid, the same pressure is transmitted unchanged to all parts of the fluid, no matter what the shape of the container holding the fluid
winch
a machine consisting of a small cylinder, a crank or handle,
and a cable, used for lifting and pulling
radius
the distance in a straight line from the centre of a circle
to the circle’s circumference (outer boundary)
friction
the force resisting the relative motion of solid surfaces,
fluid layers, and material elements sliding against each other
a machine can never be 100% efficient
because there is always friction
efficiency
a measure of how much input work (effort)
is transferred into output work (load)
Efficiency = Work Output work (J)
———————————
Work Input Work (J)
Law of Conservation of Energy
energy is never created or destroyed
it is only transformed from one form to another
sometimes energy is lost to friction, heat or sound
If a machine gives a force advantage, then the effort force….
is less than the load force
