Ch.4 Sec.1 Flashcards
(9 cards)
Work
Transfer of energy when a force is applied over a distance; Measured in joules
Over a distance, it is the transferred energy when the force is applied; it is also measured in joules
Ex. Pushing against a desk and it moves
Force with Parallel Motion
They are the same direction, work is equal to force multiplied by distance
Going the same way and the work is equal to the distance multiplied by the force
Ex. Lawnmowing
Force with Perpendicular Motion
The work from that force is zero
The work force equals zero
Ex. Holding your books at a 90 degree angle
Machines
Device that makes doing work easier by increasing the force applied to an object, changing the direction of an applied force, or increasing the distance over which of force can be applied
It increase the force applied onto an object, changing to direction of an applied force, and/or increasing he force applied over a distance is how it makes work easier
Ex. Ramp
Simple Machines
Machine that does work with only one movement
One movement working device
Ex. Lever, Pulley, Wheel and Axle, Inclined Plane, Wedge, Screw
Types of Simple Machines
Lever, Pulley, wheel and axle, inclined plane, screw, and wedge
Compound Machines
Machine that is a combination of two or more simple machines
One or two simple machines combined
Ex. Scissors, Bike
Efficiency
Ratio of the output work done by the machine to the input work done on the machine, expressed as a percentage
Output work ratio done by the machine to he input work done on the machine; equals percentage
Ex. Reduce Friction = better efficiency
Effectiveness or Mechanical Advantage
Ratio of the output force exerted by the machine to the input force applied to the machine
Output forces ratio by the machine exerted on the input force applied to the machine
Ex. Increase Speed, Change Direction of Force, Increase Force
