ASVAB Mechanical

an induction clutch works by

a) magnetism

b) pneumatics

c) hydraulics

d) friction

magnetism

if a first-class lever with a resistance arm measuring 2 feet and an effort arm measuring 8 feet are being used, whats the mechanical advantages?

a) 2

b) 4

c) 6

d) 1

“MA = 8 ÷ 2 = 4”

air pressure at sea level is about 15 psi. whats the amount of force excerted on top of your head, given a surface area of 24 square inches?

a) 360 pounds

b) 625 pounds

c) 5/8 pound

d) 180 pounds

“F = 15 × 24 = 360 pounds.

the force produced when a boxers hand hits a heavy bag and “bounces” off it is called

a) response time

b) bounce

c) recoil

d) gravity

recoil

a cubic foot of water weighs about 62.5 pounds. if an aquarium is 18 feet long, 10 feet deep, and 12 feet wide, whats the approximate pressure in pounds per square inch (psi) on the bottom of the tank?

a) 2 psi

b) 4 psi

c) 5 psi

d) 7 psi

4 psi

springs used in machines are usually made of

a) plastic

b) bronze

c) nylon fiber

d) steel

steel

a clutch is a type of

a) universal joint

b) coupling

c) gear differential

d) cam follower

coupling

a single block-and-fall called a

a) fixed pulley

b) gun tackle

c) runner

d) sheave

runner

if a house key, a wooden spoon, a plastic, and a wool jacket are all the same temperature. on a cool day, which one feels the coldest?

a) key

b) spoon

c) hanger

d) jacket

key

a way to determine the amount of power being used is to

a) multiply the amount of work done by the time it takes

b) multiply the distance covered by the time it takes to move a load

c) divide the amount of work done by 550 pounds per second

d) divide the amount of work done by the amount of time it takes

divide the amount of work done by the amount of time it takes

a wood tool, a silver tool, and a steel tool are placed in boiling water for cleaning. which tool will get hot the fastest?

a) steel

b) wood

c) silver

d) all three are equally hot

silver

force

mass × acceleration

vector quantities

forces that has both size and direction

equilibrium

a stable situation in which forces cancel one another

velocity

the speed and direction of a moving object

acceleration

the rate at which velocity changes

pressure

force (in pounds) ÷ area (in inches)

work

force × distance

tension is measured in

pounds-force or newtons

work is measured in

foot-pounds

power

work ÷ time

power is measured in

horsepower (hp)

1 horsepower

33,000 foot-pounds per minute or 550 foot-pounds per second

mechanical advantage

when a machine multiplies the force you use

mechanical advantage

resistance ÷ effort = output force ÷ input force

fulcrum

point of support to reduce resistance and multiply the effect of effort

resistance arm

the part of a lever that applies a force on an object

effort arm

the part of a lever that you apply an input effort force to.

to determine how much a lever reduces the amount of effort needed to do work

length of effort arm ÷ length of resistance arm = resistance force ÷ effort force

mechanical advantage of using a lever

effort arm ÷ resistance arm

mechanical advantage of using a ramp

length of ramp ÷ height of ramp = weight of object being moved ÷ force required to move object

block and tackle pulleys

make lifting heavy objects easier or change the direction of the pull

a simple pulley

force must equal the weight of the object

gears

used to change direction, increase or decrease speed, or increase or decrease force

if you have an even number of gears connected in a series

the first and last gear turn in opposite directions

if you have an odd number of gears connected in a series

the first and last gear turn in the same direction

number of teeth

the speed at which a gear rotates depends on the ______

bevel gears

used to connect gears that have shafts (that aren't parallel to one another) at different angles

drive other pulleys

when connected by a system of belts, pulley can do what?

diameter of the pulley in relation to the diameter of the pulley that's driving it

how fast a pulley rotates depends of what?

wheel and axle

multiplies the effort used producing a greater force

wheel and axle

are fixed together and turn at the same time; ex. using a steering wheel

wheel and axle mechanical advantage

the relationship between the radius of the wheel and the radius of the area to which force is being applied

pitch

the distance between the ridges of the spiral (on the screw of a vise) is called the _____ of the thread

greater

the ____ the pitch of the thread, the farther the jaws of the vice move for each revolution of the handle

more

larger pitches require ____ force to rotate the handle than screws with smaller pitches do

hydraulic jack

uses a nearly incompressible liquid, such as oil, to exert force in order to move an object

mechanical advantage of a hydraulic jack

the ratio between the diameters of the two cylinders

What formula do you use to find force?

F=MA

What formula do you use to find weight?

W=MG

What formula do you use to find Work?

W=FD

What formula(s) do you use to find power?

P=W/T or P=FD/T

What formula do you use to find Kinetic Energy?

KE=1/2mv²

What formula do you use to find Potential Energy?

PE=MGH

What is the general formula to calculate mechanical advantage?

MA=Output Force/Input Force

What formula is to find the incline plane mechanical advantage?

MA=Height of Incline/Length of Incline​

What formula is to find the pulley system?

MA=Length of Effort Arm/Length of Resistance Arm

Formula for Ideal Mechanical Advantage:

IMA=Distance Input/Distance Output

Formula for Efficiency:

E=(Work Output/Work Input) x 100%

Formula for Torque:

τ=F⋅R

Formula to convert RPM to angular velocity:

ω=2π⋅RPM​/60

Formula for Gear Ratio:

GR=Teeth on Driven Gear/Teeth on Driver Gear

Formula for pulley speed relationship:

D1 x N1=D2 x N2

Formula for velocity:

V=D/T

Formula for acceleration:

A=V/T

Formula for Distance with acceleration:

D=vt+1/2at²

Pascals Principle:

P=F/A

Formula for friction:

f=μ⋅N

Normal force formula?

N=m×g

Torque is

A) the degree to which a force causes an object to rotate

B) the same as horsepower

C) a push pull

D) a force that travels in a circle

A. the degree to which a force causes an object to rotate

Speed is different from velocity because

A) Speed is measured in metric units while velocity is measured in English units

B) Velocity involves both speed and direction

C) Speed involves both velocity and direction

D) Velocity is a scalar quantity

B. Velocity involves both speed and direction

Mechanical advantage is the advantage gained by the use of ___________ in transmitting force

A) Power

B) a transformer

C) a mechanism

D) an engine

C. a mechanism

Which of the following statements about weight is NOT true?

A) Weight increases closer to the earth's surface

B) Weight is not totally dependent on mass

C) Weight is greater on planets with greater mass

D) Weight varies from location to location

B. Weight is not totally dependent on mass

Which of the following represents the mechanical advantage of a wheel and axle system where the driven wheel has a radius of 10" and drive wheel has diameter of 5"?

A) 4:1

B) 2:1

C) 1:2

D) 1:4

A. 4:1

In order to apply more toque to a bolt, a mechanic could

A) use a longer wrench

B) apply less force to the wrench

C) use a shorter wrench

D) Move the wrench more quickly

A. Use a longer wrench

A vehicle travels at a constant speed on the highway. It can be said that

A) its acceleration rate is less than zero

B) the net force acting on the vehicle are zero

C) the force applied by the vehicle's drive wheels is greater than the forces that act to slow the vehicle

D) it is accelerating at a constant rate

B. the net force acting on the vehicle are zero

A wheelbarrow is considered what type of lever?

A) a second-class lever

B) a pulley system

C) a third-class lever

D) a crank

A. a second-class lever

One pound of force is applied to move an object a distance of one foot. how much work has been done?

A) 1 foot-pound

B) 1 watt

C) 2 foot-pounds

D) 1 hertz

A. 1 foot-pound

Which of the following statements about energy is NOT true?

A) Energy cannot be created

B) The amount of energy is the universe is slowly diminishing

C) Energy cannot be destroyed

D) Energy can be converted from one form into another

B. The amount of energy is the universe is slowly diminishing

Which of the following is NOT a true statement about the principles that underlie hydraulics?

A) Liquids conform to the shape of their container

B) A liquid can be dramatically compressed in order to increase the amount of force the liquid can transfer

C) A liquid is effectively incompressible

D) When pressure is applied to a completely enclosed fluid, this pressure is transmitted to all parts of the fluid and the enclosing walls

B. A liquid can be dramatically compressed in order to increase the amount of force the liquid can transfer

In order to hit a baseball so that the ball has a greater velocity, the player must

A) hit the ball with less force

B) make contact with the ball for a longer period of time

C) apply more torque to the ball

D) hit the ball so that it travels at roughly a 45 degree angle relative to the ground

B. make contact with the ball for a longer period of time

Pressure is equal to force acting over

A) a distance

B) a period of time

C) A volume

D) an area

D. an area

What is the formula for torque?

F=ma

What is the formula for weight?

W= m(9.8)

What is the formula for pressure?

P= F/A

What is the formula for torque?

T= rF

What is the formula for Kinetic Energy?

KE = 1/2mv^2

What is the formula for Work?

Work = Force x Distance

An induction clutch works by

magnetism

If the first-class lever with a resistance arm measuring 2 feet and an effort arm measuring 8 feet are being used, what's the mechanical advantage?

4

The bottom of four boxes are shown below. The boxes all have the same volume. If postal regulations state that the sides of a box must meet a minimum height, which box is most likely to be too short to go through the mail?

No. 3

Looking at the figure below, when Anvil B lands on the seesaw, Anvil A will

rise in the air quickly

Air pressure at sea level is about 15 psi. What's the amount of force exerted on the top of your head, given a surface area of 24 square inches?

360 pounds

The force produced when a boxer's hand hits a heavy bag and "bounces" off it is called

recoil

In the figure below, if Gear 1 has 25 teeth and Gear 2 has 15 teeth, how many revolutions does Gear 2 make for every 10 revolutions Gear 1 makes?

about 16 2/3

A cubit foot of water weights about 62.5 pounds. If an aquarium is 18 feet long, 10 feet deep, and 12 feet wide, what's the approximate pressure in pounds per square inch (psi) on the bottom of the tank?

4 psi

Springs use in machines are usually made of

steel