Mechanical Comprehension

Question 1

What type of strength helps a material resist force acting to pull it apart?
A Shear
B Torsion
C Compression
D Tensile strength

Answer 1

D Tensile strength

Tensile is synononymous to Tension, pull apart

Question 2

Cog A has 12 teeth, Cog B has 18. If Cog B completes two full retations, how many rotations will cog A complete?
A 1
B 1.5
C 2
D 3

Answer 2

D 3

= 3/2 or gear ratio of 1.5 x 2 rotations = 3

or gear ratio of 1.5
x 2 rotations = 3

18/12 common factor of 6 = 3:2

Question 3

If a 12 pound weight attached to a spring stretches it 2 inches, how much will it stretch with an 18 pound weight attached to it?
A 3
B 4
C 6
D 8

Answer 3

A. 3

12/2=18/x
36=12x
X=3

F=kx
F= Force appalied
K= Spring constant
X Extenstion of spring

Question 4

A beam has a maximum strength of 3000psi. A 500ibs wegiht is added to the center of the beam and creates an added stress of 1000psi. How much more weight can be added before reaching its breaking point?
A 500
B 1000
C 1500
D 2500

Answer 4

Can only put 1000ibs, 1500ibs would cause break the psi
500ibs=1000 psi

Question 5

The boat oars or paddles are and example of what simple machine?
A Screw
B Wheel and axel
C First class lever
D Block and tackle

Answer 5

C First class lever

Full crum is in the middle of the paddle, between effort and load.

Question 6

The definition of a vacuum is
A Absence of matter
B Force exerted by the weight of the air
C Space influence by the atmosphere
D Space in which pressure is higher than atmospheric pressure

Answer 6

A Absence of matter

is space devoid of matter

Question 7

Gear A has 36 Teeth, Gear B has 18 teeth. If Gear A makes 150 revolutions per minute ( RPM) How many RPMs does Gear B make?
A 36
B 72
C 150
D 300

Answer 7

D 300

36/18 common factor 18 = 2:1
150 x 2 = 300

Question 8

Spaces are placed between slabs of concrete in city sidewalks to
A improve traction
B prevent water from puddling
C collect dirt and other debris
D allow for expansion and contraction

Answer 8

D allow for expansion and contraction

Expands = hot, Contracts = cold

Question 9

Gear A 28 inches diameter and Gear B 14 inches in diameter are connected by a belt. If wheel A makes one complete rotation, how many rotations will wheel B make?
A 1/2
B 1
C 2
D 3

Answer 9

C 2

28/14 Common factor of 14
2:1 gear ration
Every A rotation = B 2 Rot.

Question 10

Is it true that frictional forces
A Prevent motion
B only operate vetical directions
C always aid forces producing motion
D always opposes producing motion

Answer 10

D always opposes producing motion

Question 11

Which objects has the most structural strength?
A triangle
B rectangle
C septagon
D T Shape

Answer 11

A triangle

Considered strongest structural shape

Question 12

Centrifugal force is the
A force of attraction
B outward force caused by rotation
C force of fluid on an immersed object
D force resistion motion between one set of molecules and another

Answer 12

B outward force caused by rotation

Swing ride at a carnival are forced outward by rotation

Question 13

If 100 pounds of force are applied over an area of 2 square inches, then pressure would be
A 5
B 50
C 100
D 200

Answer 13

B 50 psi

P=F/A
100/2= P

Question 14

How much force is needed to apply 50 ft ib of torque to apply 50 ft ib of torque to a bolt using 2 ft long wrench?
A 100
B 50
C 40
D 25

Answer 14

D 25 pounds

T= rF
50=2F
50/2= 25
25=f

Question 15

If a force of 200 pounds is exerted over an area of 10 square inches, what is the pressure in terms of PSI?
A 10
B 15
C 20
D 200

Answer 15

C 20

P=F/A
200/10=P
20=P

Question 16

In engineering terms, if a building does not deflect or move when a force is applied, it is said to be
A Steady
B Rigid
C perpetual
D Constant

Answer 16

B Rigid

Resistance to deformation or bending forces, essentially it’s stiffness

Question 17

Which of the following is NOT Newtons Three laws of motion.
A An object will staty at rest
B E = MC²
C For every action, there is and qeual and opposite reaction
D F = ma

Answer 17

B E = MC²

A = Ist
C= 3rd
D 2nd

Question 18

What makes it more difficult to push a block of wood on a sandpaper surface than on a glass surface?
A gravitational force
B centrifugal force
C frictional force
D kenetic force

Answer 18

C frictional force

Question 19

A water pipe bursting when it freeze is an example of water’s ability to:
A expand
B contract
C vaporize
D subliminate

Answer 19

A expand

From fluid to and molecular structure of water

Question 20

Which of the following is a true principle of inertia?
A It is the tendency of an object to change its backward motion
B It is a force that causes objects to move
C It is proportional to the mass of an object
D It is a natural phenomenon that exists when friction is absent

Answer 20

C It is proportional to the mass of an object

Newtons 1st Law: Object will not change its motion

Question 21

A steel wedge is place next to a heavy stone. When the worker strikes the wedge, what will likely happen to the stone?
A Stone will stay level and rise
B Only left side of the stone will rise
C Only right side of stone will rise
D Stone will stay level and move right

Answer 21

B Only left side of the stone will rise

Going under left side and rise

Question 22

What is the force acting of the log to keep it afloat?
A friction
B torsion
C inertia
D Buoyancy

Answer 22

D Buoyancy