Simple Machines & Mechanical Advantage RHS Technology Education.
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Transcript of Simple Machines & Mechanical Advantage RHS Technology Education.
Simple Machines & Mechanical AdvantageRHS Technology Education
Simple Machines are Designed to…
• Transfer kinetic energy (the energy of motion) • Reduce the effort needed to move a load• Change the direction or amount of motion• Change the type of motion (rotary to
straight line)
Mechanical Advantage
• What is Mechanical Advantage?• a measure of how much the effort is decreased by the
simple machine.
• Ideal Mechanical Advantage (IMA) ignores internal friction
• How do I calculate IMA?• IMA=Effort distance/Resistance distance
Lever
• A lever is a stiff bar which rotates around a point called the fulcrum.
• Can you list some examples of a lever?
1st Class Levers
2nd Class Lever
3rd Class Lever
Mechanical Advantage of Lever
• IMA= Effort Arm (Effort to Fulcrum)/Resistance Arm (Resistance to Fulcrum)
Wheel and Axle• A Wheel & Axle change rotary motion into linear motion• IMA= Wheel Radius/ Axle Radius
Fixed Pulley
Movable Pulley
Block & Tackle
The Three Types of Pulleys
Pulley• IMA = is determined by counting the number of supporting
ropes• Last one over top does not count!
Inclined Plane
• IMA= Length of Slope/ Height of the Slope
Wedge
• IMA= Length of Sloped Edge / Separation Surface
Effort
Inclined Plane
Effort
Wedge
Inclined Plane vs. Wedge
ScrewA screw works by using a twisting motion to create torsion
Screw• IMA= 3.14x Diameter/Distance between threads (lead)
Practice Problem• Calculate the
mechanical advantage of the screw shown
• In this example:• The diameter is (1/4)”
• The lead is 1/20
• What is the IMA of this screw?