chapter 3 Flashcards
Work
the transfer of energy that occurs when a force is applied over a distance
Work Equation
work (in joules) = force (in newtons) x distance (in meters)
W = Fd
Power
rate at which work is done
Power Equation
power (in watts) = work (in joules)/time (in seconds)
P = w/t
Mechanical advantage
the ratio of a machine’s output force produced to the input force applied
Mechanical advantage
output force (in newtons)/ input force (in newtons)
MA = F out / F in
Efficiency
a machine is the ratio of the output work to the input work
Efficiency (in %)
output work (in joules)/ input work (in joules) x 100%
Efficiency = W out/ W in x 100%
Simple machines
do work using only one movement
Lever
a simple machine made up of a bar that pivots, or rotates, about a fixed point
Fulcrum
The point about which a lever pivots
Wheels and axle
is an axle attached to the center of a wheel and both rotate together
Ideal mechanical advantage
radius of wheel (in meters)/ radius of axle (in meters)
IMA = R wheel/ R axle
Inclined plane
a flat, sloped surface, or a ramp
Ideal mechanical advantage
Inclined Plane equation
length of inclined plane (in meters)/ height of inclined plane (in meters)
IMA = l/h