Simple Machines Flashcards
What are forces?
Push or pulls that can be balanced or unbalanced. If unbalanced, they can change the shape of objects and change the way they are moving.
Name 6 simple machines.
Wheel and axel, lever, pulley, screw, wedge, inclined plane.
What is work?
The transfer of energy caused by a force.
Why do we need simple machines?
They make our work easier. We won’t need to use as much force with simple machines.
What is a machine?
Instruments that reduce effort to do work.
What is a pulley?
A rope that moves over a wheel.
What forces in a pulley are always equal?
Upwards force = Downwards force
What happens if you add more pulleys?
It decreases the amount of force needed to lift an object. However, the rope will need to be pulled further so the same amount of work is done.
What are pulleys function?
Used to lift heavy objects.
What are the three parts of a pulley?
Load, rope, and wheel.
What is a lever?
A bar that balances on a fixed point and moves like a seesaw.
What are other words to describe fixed point?
Fulcrum and pivot.
What are the 2 main parts of a lever?
The bar and the fulcrum.
What do you need to work a lever?
Bar, fulcrum, load, effort.
What is load?
The object you’re lifting.
What is force?
Effort applied to make an object move.
What is effort?
Force applied to make an object move.
What does a fulcrum do?
A fulcrum does not move and it provides support/balance to the bar.
Explain how a see-saw works.
Your friend is sitting on one end (the load), and you are sitting on the other(the effort). You exert force on your end, trying to lift your friend off of the ground. When you push down on the seat, your effort lifts your friend up, while the fulcrum acts as the pivot, making the see-saw go up and down.
Why is it easier to lift your friend up using a see-saw, rather than picking them up manually?
It’s easier to lift them up through the see-saw because less work is required to lift your friend.
What happens if the length of the bar increases?
The effort needed decreases.
Why do longer levers work better?
They allow a larger force to act upon the load than is supplied by the effort.
What type of multipliers are levers?
Force multipliers.
What is a force multiplier?
They reduce the amount of force needed to lift an object. Designed to produce increased forces.
What is a distance multiplier?
Produce decreased forces but increase the distance an object moves.
The law of conservation of energy?
The amount of work done by the lever cannot be greater than the work done by the pushing force.
What is the wheel and axle?
Two or more wheels connected by an axel (spindle). The wheel turns with or around the axle.
What is an example of a wheel and axel?
A wheelbarrow.
What are wheelbarrows used for?
They are used by gardeners and builders to carry loads from place to place.
How do wheelbarrows work?
When you lift the wheelbarrow, the handles move through a bigger distance than the load does.
What is the calculation for W, F, and D?
W = F x D F = W/D D = W/F
What are the units for W, F, and D?
W = J (Joules) F = N (Newtons) D= m (Meters)
What are the calculations for W, MA, and F?
W = MA x F MA = W/F (how many pulleys there are) F = W/MA
What are the calculations for ID and OD?
ID = OD x MA OD= ID/MA
What is ID and OD?
ID = Input distance. Distance travelled by the rope. OD = Output distance. Distance travelled by the load.
What is Potential Energy?
Energy due to height.
What is the Calculation for P.E?
Mass x Gravity x Height
What are the units for M, G, and H?
M = Kg G = 10 m/sec H = m
Are moment and workdone the same?
Yes, except moment is calculated in Nm, while workdone is calculated in J.
What is the formula for M, F, and D?
M = F x D F = M/D D = M/F
