Simple MachinesSimple MachinesThere are six kinds of simple machines:There are six kinds of simple machines:

1.1. Inclined Plane – Inclined Plane – 2.2. Pulley-Pulley-3.3. Lever – Lever – 4.4. Wheel and Axle- Wheel and Axle- 5.5. Screw –Screw –6.6. Wedge -Wedge -

rampramptop of a flag poletop of a flag pole

crowbarcrowbarscrewdriverscrewdriver

nuts & boltsnuts & bolts

zipperszippers

Compound machine – more then one simple machine

Inclined Plane and PulleysInclined Plane and PulleysInclined Plane: when length increases, force

decreases

Pulleys are just inclined planes that move

Pulleys can be fixed

Or moveable (move)

(don’t move)

Fixed & moveable pulleys together are called:

(bait and tackle)

LeversLeversLevers help __________ your force.increase

The levers FULCRUM is the part that _______

______ move.

does

not

fulcrum

Types of LeversTypes of LeversThere are __________ types of leversthree

1. First Class: (fulcrum in the___________)

2. Second Class: (fulcrum on an _____, effort

on the end)

3. Third Class: (fulcrum on the ______,

effort in the middle)

crowbarmiddle

wheelbarrowend

endbroom

MachinesMachines

Machines make work easier three ways.

• by changing the ______ of the force.

•by changing the ___________ of the force.

•by changing the _______ of the force.

size

direction

speed

Most machines help by multiplying your _____________________. This is called _____________________________________

Effort (Force)Mechanical Advantage

Mechanical Advantage (M.A.)Mechanical Advantage (M.A.)

MA = resistance force or output force effort force input force

output

input

masslifted pulled pushed

force

Efficiency (E)Efficiency (E)Efficiency compares the _______ ______ to the _______ ______

Work Output is the work done by the _________.( = ______________ x ________________)

Work Input is the work you put into the _________.( = ______________ x ________________)

output workinput work

machine

machine

resistance force resistance distance

effort force effort distance

EFFICIENCY Problem 1EFFICIENCY Problem 1Efficiency = _____________

X 100OUTPUT WORK INPUT WORK

Problem: You do 1,500J of work when using a hammer. The hammer does 750J if work on a nail. What is the efficiency of the hammer?

Output Work = Input Work =

750J

1,500J

E = 750J 1,500J

X 100

E = 50%

Efficiency Problem 2Efficiency Problem 2Problem: The input work of a triple pulley is 300 J. The pulley system output work for lifting the block is 125 J. Find the efficiency.

Output Work = Input Work =

E = 125J 300J

X 100

E = 41.7%

125J300J

The Efficiency of a machine will never be 100%. The system will lose work in the form of _________ due to _________ etc. Machine parts wear down.

HEATFRICTION

Simple MachinesSimple MachinesThere are six kinds of simple machines:There are six kinds of simple machines:

1.1. Inclined Plane – Inclined Plane – 2.2. Pulley-Pulley-3.3. Lever – Lever – 4.4. Wheel and Axle- Wheel and Axle- 5.5. Screw –Screw –6.6. Wedge -Wedge -

Compound machine – more then one _____________

Inclined Plane and PulleysInclined Plane and PulleysInclined Plane: when length increases, force

Pulleys are just inclined planes that

Pulleys can be fixed

Or moveable

Fixed & moveable pulleys together are called:

LeversLeversLevers help __________ your force.

The levers FULCRUM is the part that _______

______ move.

Types of LeversTypes of LeversThere are __________ types of levers

1. First Class: (fulcrum in the___________)

2. Second Class: (fulcrum on an _____, effort

on the end)

3. Third Class: (fulcrum on the ______,

effort in the middle)

MachinesMachines

Machines make work easier three ways.

• by changing the ______ of the force.

•by changing the ___________ of the force.

•by changing the _______ of the force.

Most machines help by multiplying your _____________________. This is called _____________________________________

Mechanical Advantage (M.A.)Mechanical Advantage (M.A.)

MA = resistance force or output force effort force input force

Efficiency (E)Efficiency (E)Efficiency compares the _______ ______ to the _______ ______

Work Output is the work done by the _________.( = ______________ x ________________)

Work Input is the work you put into the _________.( = ______________ x ________________)

EFFICIENCY (E)EFFICIENCY (E)Efficiency = _____________

X 100

Problem: You do 1,500J of work when using a hammer. The hammer does 750J if work on a nail. What is the efficiency of the hammer?

Output Work = Input Work =

Efficiency Problem 2Efficiency Problem 2Problem: The input work of a triple pulley is 300 J. The pulley system output work for lifting the block is 125 J. Find the efficiency.

Output Work = Input Work =

X 100

The Efficiency of a machine will never be 100%. The system will lose work in the form of _________ due to _________ etc. Machine parts wear down.