moments Flashcards
what is a moment in simple terms?
turning effect of a force around a pivot point
why is understanding moments important?
studying balance, stability and rotational motion
what causes an object to turn?
a force or system of forces
what is the definition of a moment?
a moment is the product of the force and perpendicular distance from the pivot
what is the equation of moment?
force x perpendicular distance
what is the pivot point?
the point around which the object can rotate or turn
where is pivot on a seesaw?
directly in the middle
what direction can be moments in?
moments can be clockwise or anticlockwise
what does the direction of the moment depend on?
the direction of the force relative to the pivot
what is the lever arm?
perpendicular distance between the line of action of the force and the pivot,
it directly affects the magnitude of the moment
what does a longer lever arm produce ?
larger moments for the same force
what is the unit of moments
newton metre (NM)
what is the principle of moments?
for an object to be balanced the total clockwise moment must be equal to the total anti clockwise moment
total clockwise moment =
total anticlockwise moment
what do spanners and levers use?
both use moments
what are spanners used for?
to turn nuts and bolts, if you need to undo a nut that is very tight you can use a short spanner and apply a large force or use a long spanner and apply small force
why would you use a longer spanner?
using the longer spanner increases the distance from the pivot, this reduces the amount of force needed to undo the nut from the bolt
what does a lever consist of?
a pivot, effort, load
what are some examples of effort pivot load
seesaw, crowbar, scissors
what are some examples of pivot load effort
wheelbarrow, nutcracker
what are some examples of pivot effort load
tweezers, cooking tongs
explain example of removing lid of paint can in terms of levers
- removing lid requires a large force on lid
- screwdriver acts as a lever
-pivot is the edge of a can
-very close to where the strong push is needed to lift the lid to open the can
-screwdriver with long handle is best because you can push down on handle of screwdriver with a small force and open can
how are moments used in engineering?
engineers use moments extensively in designing structures, bridges and machines. calculating and considering moments makes sure the safety and stability of constructions
how is equilibrium achieved?
when an object is balanced and does not rotate
why are moments important in rotational motion
helps explain how objects rotate and how energy is transferred in systems involving rotation
