## Presentation on theme: "WORK & SIMPLE MACHINES GRADE 6 GRADE 6 Mrs. Figoten."— Presentation transcript:

WHAT IS WORK? WORK = FORCE X DISTANCE
Joules = newtons (N) X meters (m)

CALCULATING WORK -----------------------------------------------
The crane uses 30 newtons of force to lift the iron block 8 meters. Work done  = Force x Distance moved  = 30 newtons (F) x 8 meters (D)  = 240 Joules How much work was done? Because the block is held up high, it becomes:    potential energy = 240 J (due to gravity) If the mass then falls freely to the ground, just before it hits the ground, it’s . . . 240 J of kinetic energy

Longer Plane = More Distance
INCLINED PLANE Flat surface with 1 end higher than other Used to gradually raise or lower objects EFFICIENCY Friction reduced if surfaces of plane & load are smooth MECHANICAL ADVANTAGE (MA) INPUT FORCE DISTANCE Longer Plane = More Distance

Examples of INCLINED PLANES

Longer Point/Edge = More Distance
WEDGE Type of inclined plane Has 1 or 2 sloping sides Force applied to wide end Narrow end driven into object– push object apart EFFICIENCY Friction reduced if edge sharper MECHANICAL ADVANTAGE (MA) INPUT FORCE DISTANCE Longer Point/Edge = More Distance

Examples of WEDGES

SCREW Type of inclined plane Wrapped around a rod Direction of force changed Amount of force increased EFFICIENCY Increased when threads closer MECHANICAL ADVANTAGE (MA) INPUT FORCE DISTANCE More threads = More Distance

Examples of SCREWS

LEVER Does work by turning around FULCRUM (fixed point)
Force applied to do the work = EFFORT Force created by LOAD when trying to move it = RESISTANCE EFFICIENCY GREATEST WHEN WORK REQUIRES THE LEAST EFFORT

Longer Effort Arm = More Distance
MECHANICAL ADVANTAGE (MA) INPUT FORCE DISTANCE Longer Effort Arm = More Distance effort arm load effort fulcrum

LESS EFFORT NEEDED TO DO THE WORK
LESS DISTANCE BETWEEN LOAD & FULCRUM LESS EFFORT NEEDED TO DO THE WORK

TYPES OF LEVERS There are 3 Classes

FIRST CLASS LEVER

SECOND CLASS LEVER

THIRD CLASS LEVER

Summary of LEVER CLASSES
1st Class 2nd Class 3rd Class By whether the fulcrum, load, or effort is in the center. How do you know what class a lever is? Fulcrum= Pivot Point Effort force = input force Load (Resistance) = output force

Turning larger wheel = More Distance
WHEEL & AXLE Large wheel fixed to smaller wheel (or shaft) called an axle Both turn together Effort usually on larger wheel, moving load of axle MECHANICAL ADVANTAGE (MA) INPUT FORCE DISTANCE Turning larger wheel = More Distance

Think of as lever rotating in circle around center fulcrum
Like steering wheel (larger wheel) on column (axle) Wheel & axle turn together EFFICIENCY: Reduced friction with lubricant

HOW DOES WHEEL & AXLE WORK?

Rope around more wheels = More Distance
PULLEY Wheel with groove Allows rope to ride on wheel without slipping off MECHANICAL ADVANTAGE (MA) INPUT FORCE DISTANCE Rope around more wheels = More Distance

TYPES OF PULLEYS FIXED PULLEY (like clothesline or flagpole)
Pulley stays in one position Moves LOAD up, down or sideways Changes DIRECTION of force Does not reduce EFFORT

TYPES OF PULLEYS MOVABLE PULLEY Moves along with LOAD Reduces EFFORT
(for lifting or lowering heavy objects) Moves along with LOAD Reduces EFFORT Increases DISTANCE

Examples of PULLEYS

GEARS Wheels with teeth, so one turns the next
SMALLER gear turns FASTER than larger gear One gear makes other gear beside it turn in OPPOSITE DIRECTION Speeds things up,slows them down, changes direction of force GEARS

Compound machines are made of 2 or more simple machines.

Illustrating… COMPOUND MACHINES Made of at Least 2 SIMPLE MACHINES
KIDS’ INVENTIONS Illustrating… COMPOUND MACHINES Made of at Least 2 SIMPLE MACHINES

This is the Chore 3,000. He can clean your room. It can take the trash out and do other chores. He is made of gears, screws and pulleys..

This simple machine is The Kids’ Chore.
Our simple machine does a lot of stuff such as recycles cans and then washes them, and then has them come to be used again. Another thing it does is washes clothes and hangs them back up for kids. It also cooks popcorn and pours drinks. Another thing it does is dusting, it will dust anything for you. The simple machines we used were the wheel and axle,inclined plane, just wheels, pulleys, and gears.

This is the Chore 5,000. He can clean your room. It can take the trash out and do other chores. He is made of gears, screws and pulleys.