Work is not affected, only force and distance
efficiency = (3000N x 1.5m)/ (600N x 10m) x 100% = 75%
IMA = effort distance/ resistance distance = length of slope/ height (or width) of slope
3500 N x 20 m = 70000J
Efficiency = Resistance Force x Resistance distance/ Effort force x effort distance
lever, pulley, wheel and axle
efficiency = 300J /500J x 100% = 60%
work in = work out
lever, pulley, wheel and axle, wedge, incline plane, screw
Threads are spiraled incline plane and point is wedge
Joules
IMA = wheel radius/ axle radius = 30 cm/ 1.5 cm
MA = 500N/ 20N = 25
Power = (600n + 23,400N) x 30m/ 90 s = 8000W = 8 kW
Power = 500N x 4m/ 5 seconds = 400W
The machine with the fastest rate.
Mechanical Advantage = Resistance Force/ Effort Forct
levers and wedges
varies
Efficiency = (Work out/ Work in) x 100%
Watts
Power = Work / Time
IMA = effort arm length/ resistance arm length
Work = force x distance
Some work is always converted to heat due to friction.
Give the unit of measure for work.
What is the unit of measure for power?
In an ideal machine how is work in related to work out?
You are comparing two snowblowers. Both will put of the same amount of work, but the work is done at different rates. Which machine will have the greatest power?
How much power does a person weighing 500 N need to climb a 4m ladder in 5 seconds?
In practice, machines are never 100% efficient. Why is work out always less than work in?
How would you calculate efficiency when only force and distance (not work) are known?
All simple machines fit into which two families (or types)?
How do machines affect work?
A worker applies an effort force of 20 N with a crowbar to pry open a window with a resistance force of 500 N. What is the mechanical advantage of the crowbar?
What is the formula for power?
What is the formula for mechanical advantage?
A 600 N passenger is inside a 23,400 N elevator that rises 30 m in exactly 90 seconds. How much power is needed to raise the elevator?
How would you calculate the ideal mechanical advantage of a lever?
List the 3 machines that are considered levers
Calculate the work required to move a 3500 N crate a distance of 20 m.
Calculate the efficiency of a machine that does 300J of work when running but requires an input of 500J of work to operate.
A box weighting 3000N must be place in a truck 1.5 m off the ground. A worker used a force of 600 N to push it up a ramp with a length of 10 m. What is the efficiency of the incline plane?
List the6 types ofsimple machines.
What is the formula for efficiency of a machine?
Calculate the ideal mechanical advantage of a unicycle with a wheel radius of 30 cm and an axle radius of 1.5 cm.
Give the formula for work.
Identify 3 simple machines used in the Rube Goldberg machine.
How would you calculate the ideal mechanical advantage of an incline plane (or wedge)?
List 2 ways a screw is a wedge.
