21 terms

Jackson Work and Machines Test

What is work?
Transfer of energy through motion
2 things that must be present for work to actually occur
1. There must be motion
2. Motion must be in the same direction as the force
Work unit
Joules (J)
Formula for work
Force • Distance = work
Power unit
Power Formula
Work ÷ time = power
What is a machine?
Something that makes work easier
Simple machines
-Wheel and axle
-Inclined plane
Simple machine examples
Lever- seesaw, crow bar
Pulley- window blinds, sailboat pulleys
Wheel and axle- ferris wheel, door nob, car tire
Inclined plane- staircase, ramp
Screw- screws, spiral staircase, vice
Wedge- knife, wood stopper
lever definition
a rigid bar that pivots around a fulcrum
pulley definition
a wheel and axle with a grove and a rope and chain connected to it
wheel and axle definition
a wheel that rotates around a shaft (axle)
inclined plane definition
a sloping surface
screw definition
spiral inclined plane around a cylinder
wedge definition
inclined plane with 2 sloping sides
lever MA
MA = effort arm length / resistance arm length
pulley MA
count all the ropes besides the one that is being pulled down
wheel and axle MA formula
wheel radius ÷ axle radius = MA
inclined plane MA formula
length ÷ height = MA
screw MA
closer the threads are the higher the MA
Wedge MA
thinner the blade the higher the MA