Chapter 3

Question 1

Explain the difference between potential and kinetic energy

Answer 1

Kinetic is energy in motion

Potential is stored energy

Question 2

What two units are used to describe mechanical force

Answer 2

Pounds

Or

Newtons

Question 3

Two distinct qualities of mechanical force

Answer 3

Magnitude

Direction

Question 4

Scaler vs vector value

Answer 4

Secular value has only magnitude

Vectors have magnitude AND direction

Question 5

Formula for torque

Answer 5

Torque in lb-ft (N-m)

Equals

Force in pounds
X
Length of lever in ft (or meters)

Question 6

How would you find torque in a rotating wheel?

A 6 in radius wheel pulled by a pull motor starter that is 6 inches long

Answer 6

The lever arm is the radius of the wheel and the force is applied at the edge of the wheel

Torque equals 15 lb-ft

Question 7

Definition of mechanical work

Answer 7

1. applied FORCE must act on an object

2. Object must MOVE while force is applied

Question 8

Formula for mechanical work

Answer 8

Mechanical Work (in ft-lb)
Equals

Force applied to an object
X
Distance moved in feet

Question 9

One radian equals

Answer 9

57.296 degrees

Question 10

Work done by torque formula

Answer 10

Work (done by torque in ft-lbs)
Equals
Force applied by torque in ft-lbs
X
angel of oration (in radians)

W=T x theta

Question 11

What is formula for amount f work done by torque in horsepower

Answer 11

Torque
Equals
Rated horsepower x 5252
Dived by
Rated speed in RPM

Question 12

List the 6 simple machines

Answer 12

WIPSLW
Wheel and Axle
Incline Planes
Pulley
Screw
Lever
Wedge

Question 13

1st class lever

Where is fulcrum,load and effort

Answer 13

EFFFORT FULCRUM LOAD

Pliers are a 1st class lever

1st grade Sea saw

Question 14

2nd class lever

Where is load fulcrum and effort

Answer 14

FULCRUM LOAD EFFORT

like a wheel barrow where the fulcrum is the wheel

2nd grade Moving

Question 15

3rd class lever

Where is fulcrum load and effort

Answer 15

LOAD EFFORT FULCRUM

Throwing a baseball

3rd grade-t ball!

Question 16

What is sacrificed so that effort is minimized

Answer 16

Distance

Question 17

Definition of mechanical advantage

Answer 17

The ratio of the input to the output force converted by a simple machine

Question 18

Mechanical advantage of a wheel and axle

Answer 18

Is the ratio between the wheel RADIUS and the axle RADIUS

Question 19

Lever on a wheel is

Answer 19

Always the radius

Question 20

How to determine force required for lifting a load on a block and pulley

i.e. A 200lb load support by 5 ropes(not including final rope)

Answer 20

Divide the load force by the number of support ropes
(Does NOT include final rope)

Requires 40 pounds of downward force

Question 21

MA of an incline plane

Answer 21

Is the vertical distance raised in ratio to the distance moved (the hypotenuse)

Question 22

Work is

Answer 22

Equal to force
Times
Distance

Question 23

A grooved pulley

Answer 23

Called a sheave

Question 24

Why does a pulley provide MA

Answer 24

Because it allows the load to be supported by more than one rope

Question 25

Equilibrium

A plane

Answer 25

All forces acting on an object cancel eachother

Something can be at equilibrium and still move though…
A plane canceling gravity wth the jets still glides

Question 26

List the 6 types of energy

Answer 26

MECHLiNe
mechanical
Electrical
Chemical
Heat
Light
Nuclear