GENERAL SCIENCE TERM 1 (2ND SUMMATIVE TEST LESSON)

lessons include: simple and compound machine, characteristics of an efficient machine, machine efficiency,

machine

a device that makes work more easier by modifying force or motion.

simple machine

building blocks of complex systems

lever

rigid bar that rotates around a pivot/fulcrum

wheel and axle

large wheel connected to a smaller axle

inclined plane

a flat surface set at an angle

pulley

a grooved with a rope, chain, or belt used to lift loads

screw

inclined plane wrapped around a cylinder

wedge

double inclined plane used to split or cut materialscomp

compound machines

combination of two or more simple machines

factors affecting efficiency of machine

friction

energy loss

mechanical advantage

characteristics of efficient machine

minimize friction

lesser energy losses

balance force and distance trade-off

optimize power to weight ratio

efficiency

ratio of work output to work input

efficiency formula

Efficiency = work output / work input

energy loss

input is always lost and cannot be converted into useful work

forms of energy loss

1. friction

2. heat loss

3. sound

4. material deformation

Pascal’s Principle

pressure applied to a confined fluid is transmitted undiminished in every direction

factors of Pascal’s principle

• P = Force / Area

• allows for force multiplication using different size of pistons

  • forms the basic hydraulic system

formulas

P = F / A

A = F / P

F = (P)(A)