Simple Machine Flashcards
simple machine
a simple machine is a meachanical device which is siple in structure and makes our work easier and faster.
advantages of simple machine
- helps to multiply the effort applied.
- help to apply force in convenient diretion by changinf the direction of force applied.
- help to increase the speed of work.
- help to do work safely and easily.
effort
it is the force appplied to a mahine to do work.
load
it is the foce applied by the machine on the body on which work is done.
mechanical advantage defination (formula)
the ratio of the load to the effort applied is called mechanical advantage. MA= load/effort
efficiency
effuciency of a machine is defined as the percentage ratio of output to input work.
outpur work & input work formulas
output work- load × distance travelled by load
inout work- effort × distance travelled by effort
efficiency formula
n= MA/VR×100%
perfect machine
the machine in which the iutput work is equal to the input work is called perfect machine.
lever
it is a rigit, straight or bent bar which is capable of turning about a fixed point or an axis called its fulcrum.
principle of lever
when a lever is equilibrium, the input work is always equal to the outpur work. the product of load and load arm is equal to the producg of effort and effort arm.
INPUT WORK= OUTPUT WORK
1st class lever
the lever inwhich fulcrum is located in between load and effort is called first class lever. (scissors, pliers, bran balance, handle of water pump)
2nd class lever
the lever in which load is located n between fulcrum and effort is called second class lever. (wheel barrow, lemon squeezer, nut cracker)
3rd class lever
the lever in which effort is located in between fulcrum and load is called third class lever. (thongs, fishing rod, shovel, human arm)
velocity ratio
the ratio of the distance travelled by effort to the distance travelled by load is called velocity ratio.
VR= Effort arm/ Load arm
