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Module 4- Work
Work, Power, and Simple Machines
Question | Answer |
---|---|
what is work? | the ability to cause change or when a force causes an object to move |
what is the formula for work? | w= f x d |
what is the metric unit for work? | Joule/ J |
what is the work unit equal to? | Joule= N x m |
what are the two requirements for work to be done? | the object must move and the direction of the object's motion is the same as the force |
what is the conversion of pounds to Newtons? | 4.45N= 1lb |
what is power? | how fast you are working |
what is the formula for power? | Power= work/ time |
what is the metric unit for power? | Watt/ W |
what is the power unit equal to? | Watt= J/ s |
what is a machine? | a machine is something that makes doing work easier |
how do machines make work easier? | increasing force, increasing distance, or changing the direction the applied force goes |
is work done by a machine increased or decreased? | trick question, the amount of work stays the same |
what are the 6 simple machines? | levers, inclined plane, wedge, screw, wheel and axle, and pulley |
example of levers? | First class- scissors, crowbar, hole puncher Second class- wheelbarrow, nutcracker, paper cutter Third class- broom, fishing pole, hammer, swinging a baseball bat |
examples of an inclined plane? | ramp, mountain, stairs, a slanted roof |
examples of a wedge? | knife, zipper, shovel, an ax splitting wood |
examples of a screw? | water bottle cap, a jar with a lid, medicine caps on bottles, a literal screw |
examples of a wheel and axle? | door knob, ferris wheel, windmill |
examples of a pulley system? | blinds on a window, elevator, flag pole |
how do the three types of levers differ? | first class- fulcrum is in between resistance and effort force second class- fulcrum is on one edge with R.F. then E.F. third class- fulcrum is on one edge with E.F. then R.F. |
how do you calculate IMA? | IMA= Effort arm/ output arm IMA= l/h IMA= distance from effort to ful./ distance from resistance to ful. |
how do you calculate AMA? | AMA= output force/ input force AMA= resistance force/ effort force AMA= weight of obejct/ how much it takes to work |
how do you calculate work input and output? | work input= E.D. x E.F. work output= R.D. x R.F. |
what are both of the ways to calculate efficiency? | AMA/ IMA x 100 work out/ work in x 100 |
why can you not achieve 100% efficiency in a lab setting? | due to friction, you can never get 100% efficiency unless you have an ideal machine |
what is a compound machine? | a machines that has been created by two or more machines |
what are some examples of compound machines? | scissors, escalator, a bike, crane, stapler |
what is the metric unit of horsepower? | Watts |
what is a block and tackle? | a system of pulleys consisting of fixed and movable pulleys |
how is the MA of a screw affected when the threads are very close togeher? | the closer the threads are to each other, the greater the MA |
how is the MA of a screw affected when the threads are far apart? | the farther apart the threads are, the lesser the MA |
how is the MA of a wedge affected when you sharpen it? | think of a knife, the MA increases when you sharpen it the sharper it gets, the higher the MA |
the lower the slant of an inclined plane, the ____ effort force is needed | less |
the higher the slant of an inclined plane, the ____ effort force is needed | more |
how is the MA of an inclined plane related to the slant? | the higher the slant, the greater the MA |
what is the other equation for power? | power= force x speed W= N x m/s |