WORK AND MACHINESSTUDY GUIDE

1. THE UNIT OF WORK IS CALLED A

JOULE

2. AN IDEAL MACHINE HAS AN EFFICIENCY OF

100%

YOU DO 1,200 J OF WORK USING A SCREWDRIVER. THE SCREWDRIVER DOES 900 J OF WORK ON A SCREW. WHAT IS THE EFFICIENCY OF THE SCREWDRIVER?

75%

A MACHINE CAN MAKE WORK EASIER BYCHANGING THE DIRECTION OF FORCE NEEDED TO ACCOMPLISH A TASK.

AN AX, A ZIPPER, AND A FRONT TOOTH ARE EXAMPLES OF A SIMPLE MACHINE CALLED A

WEDGE

YOU DIVIDE THE RADIUS OF A WHEEL BY THE RADIUS OF AN AXLE. WHAT ARE YOU CALCULATING?

THE IDEAL MECHANICAL ADVANTAGE OF A WHEEL AND AXLE

A CAR’S STEERING WHEEL IS AN EXAMPLE OF A SIMPLE MACHINE CALLED A(N)_______.

WHEEL AND AXLE

THE FIXED POINT THAT A LEVER ROTATES AROUND IS CALLED A(N)

FULCRUM

COMPOUND MACHINES ARE

COMBINATION OF SIMPLE MACHINES

WHEN YOU BEND YOUR ARM AT THE ELBOW, THE FULCRUM IS AT YOUR

ELBOW

IN ORDER TO DO WORK ON AN OBJECT, THE OBJECT MUST _______ AS A RESULT OF YOUR FORCE.

MOVE SOME DISTANCE

A MACHINE’S __________ IS THE NUMBER OF TIMES A FORCE EXERTED ON A MACHINES IS MULTIPLIED BY THE MACHINE.

MECHANICAL ADVANTAGE

IN A SCREWDRIVER, THE HANDLE IS THE WHEEL AND THE SHAFT IS THE _______.

AXLE

MUSCLES ARE ATTACHED TO BONES BY ___________.

TENDONS

THE MORE EFFICIENT A MACHINE IS, THE CLOSER THE ACTUAL MECHANICAL ADVANTAGE IS TO THE _______.

IDEAL MECHANICAL ADVANTAGE

A MACHINE DOES NOT DECREASE THE AMOUNT OF WORK YOU DO.

TRUE

AN INCLINED PLANE WRAPPED AROUND A CENTRAL CYLINDER IS A SCREW.

TRUE

A ROPE WRAPPED AROUND A GROOVED WHEEL IS A PULLEY.

TRUE

A SINGLE FIXED PULLEY, SUCH AS A FLAGPOLE, CHANGES THE DIRECTION OF THE INPUT FORCE.

TRUE

WHEN YOU BITE INTO A SANDWICH, YOUR FRONT TEETH ACT AS WEDGES.

TRUE

(5 POINTS) LIST THE SIX TYPES OF SIMPLE MACHINES AND GIVE AN EXAMPLE OF HOW YOU WOULD USE EACH ONE IN YOUR DAILY LIFE.

SCREW – JAR LIDINCLINED PLANE – WHEELCHAIR RAMPPULLEY – FLAGPOLEWEDGE-SHARP KNIFELEVER – BASEBALL BATWHEEL AND AXLE - BICYCLE