Trade Science

Question 1

All matter is composed of what?

Answer 1

Atoms

Question 2

Define an Alloy

Answer 2

A mixture of a metal with another metal, or non metal

Question 3

Define Mass

Answer 3

The measurement of the quantity of material in a body

Question 4

Define Density

Answer 4

The mass of a body in a given volume

Question 5

The point at which a material ruptures

Answer 5

Ultimate strength

Question 6

Define tensile strength

Answer 6

The ability of a material to resist being pulled apart by external forces

Question 7

Define compressive strength

Answer 7

The ability of a material to resist external forces pushing into or against the material

Question 8

Define shear strength

Answer 8

The ability to resist forces that try to slide part of the object along itself (shearing a rivet)

Question 9

Define fatigue strength

Answer 9

The ability to withstand repeatedly alternating stresses

Question 10

Define elasticity

Answer 10

The ability of a material to return to its original dimensions after it has been acted on by a force

Question 11

Define elastic limit (yield strength)

Answer 11

The max force that a solid can withstand without being permanently deformed

Question 12

Define plasticity

Answer 12

The ability of a material to retain shape permanently after a force is removed

Question 13

Define ductility

Answer 13

A materials ability to stretch and maintain the new shape (material being drawn through a die to create wire)

Question 14

Define malleability

Answer 14

The ability of a material to be permanently deformed by compression forces

Question 15

Define brittleness

Answer 15

Material breakage without noticeable plastic deformation. The absence of malleability. (Glass)

Question 16

Define toughness

Answer 16

Ability of a material to withstand shock loads

Question 17

Define hardness

Answer 17

A materials ability to resist force trying to penetrate it (separate the molecules)

Question 18

Thermal conductivity determines:

Answer 18

The rate of heat flow through a material

Question 19

Expansion coefficient for steel

Answer 19

For every 150•F change in temperature, each inch of length and diameter changes by 0.001” (one thou)

Question 20

How much PSI=1 Atmosphere (ATM)?

Answer 20

1 ATM = 1 bar = 14.7 psi

Question 21

Define heat

Answer 21

Energy in transit from a body at higher temperature to a body at a lower temperature

Question 22

Newtons 1st law

Answer 22

A body at rest will stay in rest and a body in motion will remain in motion at the same speed and in the same direction unless acted on by some unbalanced force

Question 23

Newtons 2nd law

Answer 23

The size of a net force (F) on an object is equal to the product of the mass (m) and the acceleration (a) of the object

F= m x a

Question 24

Newtons 3rd law

Answer 24

For every action there is an equal and opposite reaction

Question 25

General definition of work

Answer 25

Work is done whenever one kind of energy is converted to another type of energy

Question 26

First class lever

Answer 26

Fulcrum between the resistant force and the effort (see-saw)

Question 27

Second class lever

Answer 27

The resistance is between the fulcrum and the effort (wheel barrel)

Question 28

3rd class lever

Answer 28

The effort is applied between the resistance and the fulcrum (engine hoist)

Question 29

What is a vacuum

Answer 29

A container with lower pressure inside than the pressure outside (less than 14.7psia)

Question 30

What is the most accurate way of measuring a vacuum?

Answer 30

A manometer

Question 31

How do you convert PSIG to PSIA?

Answer 31

Add 14.7 to your PSIG reading

Question 32

Can fluids be compressed?

Answer 32

No

Question 33

What are the 3 ways to increase pressure in a sealed container?

Answer 33

1) increase the temperature
2) reduce the volume of the container
3) pack more gas into the container

Question 34

What is Pascal’s Law?

Answer 34

Pressure applied to a confined static fluid transmits equally in all directions at right angles to the surface of its container

Question 35

What is Bernoulli’s Principle?

Answer 35

When the velocity of a fluid increases the pressure decreases, and vice versa

Question 36

What does the Compression Ratio compare?

Answer 36

The volume of gas in a vessel before and after compression

Question 37

What is Boyle’s Law?

Answer 37

If the temperature is constant the volume of gas changes inversely to the pressure

(If pressure is doubled volume is half)

Question 38

What is Gay-Lussac’s Law?

Answer 38

If the volume is constant, the pressure exerted by the gas is directly proportional to the absolute temperature

(If the absolute temperature doubles, so does the absolute pressure)