Amt General Study Guide Ch2

Front 1

The boiling point of a given liquid varies

Back 1

Directly with pressure

Hint 1

If two values are directly related, and increasing one value or increase the other value. the boiling point of a liquid goes up as the pressure goes up, so they are said to be directly related.

Front 2

An engine that weighs 350 pounds is removed from an aircraft by means of mobile hoist. The engine is raised 3 feet above its attachment mount, and the entire assembly is then moved forward 12 feet. A constant force of 70 pounds is required to move the loaded hoist. What is the total work input required to move the hoist?

Back 2

840 foot-pounds

Hint 2

Work is determined by the formula W=F×D, where (F) is the force applied and (D) represents the distance moved. The question asks for the work required to move the hoist only; therfore, the work required is 840 foot-pounds (70 pounds×12 feet=840 foot-pounds). 1,050 foot-pounds represents the work required to lift the engine and 1,890 foot-pounds is the amount of work required to lift the engine and move the hoist.

Front 3

How much work input is required to lower (not drop) a 120-pound weight from the top of a 3-foot table to the floor?

Back 3

360 foot-pounds

Hint 3

Work is calculated through the formula W=F×D, where (F) represent the applied force or weight and (D) represents the distance the object is moved. In this example, 360 foot-pounds of work are required (120×3=360).

Front 4

In physics, which of the following factors are necessary to determine power?

1. Force exerted.

2. Distance moved.

3. Time required.

Back 4

1,2 and 3

Hint 4

To determine power (P), you must know the force (F) that is exerted, the distance (D) the force moves the object, and the time (T) required to do the work. This can be seen in the formula.

P=(F×D)/t

Front 5

Which of the following is Newton's First Law of Motion, generally termed the Law of Inertia?

Back 5

Every body persists in its state of rest, or of motion in a straight line, unless acted upon by some outside force.

Hint 5

Newton's First Law of Motion explains the effect of inertia on a body. It states that a body at rest tends to remain at rest, and a body in motion tends to remain in motion (straight line and constant velocity), unless acted on by some outside force.

Front 6

What force must be applied to roll a 120-pound barrel up an inclined plan 9 feet long to a height of 3 feet (disregard friction)?

L÷I=R÷E

L=Length of ramp, measured along the slope

I=Height of ramp

R=Weight of object to be raised or lowered.

E=Force required to raise or lower object.

Back 6

40 pounds

Hint 6

To determine the force, or effort, required to move the barrel up the ramp, use the formula given (L÷I=R÷E)

9÷3=120÷E

3=120/E

3E=120

E=40

Front 7

(Refer to figure 61)

The amount of force applied to rope A to lift the weight is

Back 7

15 pounds

Hint 7

The mechanical advantage of a pulley system is equal to the number of ropes supporting the resistance minus the rope you are pulling on. In this example, the mechanical advantage is four. This means that for every one pound of effort exerted on the rope, four pounds are lifted. In this problem, 60 pounds required a force of 15 pounds (60÷4=15)

Front 8

Which statement concerning Bernoulli's principle is true?

Back 8

The pressure of a fluid decreases at points or the velocity of the fluid increases.

Hint 8

Bernoulli's principle states that when a fluid is in motion, the outward pressure exerted decreases as the fluid velocity increases.

Front 9

What force is exerted on the piston in a hydraulic cylinder if the area of the piston is 1.2 square inches and the fluid pressure is 850 psi?

Back 9

1,020 pounds

Hint 9

Pascal's law states that any force applied to a confined fluid is transmitted equally and undiminished in all directions. The amount of force (F) applied can be determined by multiplying the fluid pressure (P) times the area (A) in which the fluid is contained the force exerted on the piston is 1020 pounds. (850psi×1.2 square inch= 1,020 pounds)

Front 10

The force that can be produced by an actuating cylinder whose piston has a cross-sectional area of 3 square inches operating in a 1000 psi hydraulic system is most nearly

Back 10

3,000 pounds

Hint 10

According to Pascal's Law, Force=Pressure× Area. Substituting the values given, the force produced is 3,000 pounds (1,000 psi×3 square inch=3,000 pounds)

Front 11

Which of the following is not considered a method of heat transfer?

Back 11

Diffusion

Hint 11

He is transferred by three methods: conduction, convection, and radiation.

Front 12

Under what conditions will the rate of flow of a liquid through a metering or fish or a jack, be the greatest (all other factors being equal)?

Back 12

Unmetered-17psi, metered pressure-5 psi, atmosphere pressure-14.7 psi.

Hint 12

Bernoulli's principle states that the pressure of a fluid decreases at points where the velocity of the fluid increases. Therefore, the flow rate (velocity) in this problem is greatest when the difference between the metered and unmetered pressure is greatest.

Front 13

I'd the volume of a confined gas is doubled (assume the temperature remains constant)

Back 13

Be reduced to one-half its original value

Hint 13

Boyle's law states that the volume of an enclosed dry gas varies inversely with its pressure, provided the temperature remains constant. Therefore, when the volume of a gas is doubled, the pressure is cut in half.

Front 14

If the temperature of a confined liquid is held constant and its pressure is tripled, the volume will

Back 14

Remain the same

Hint 14

For all practical purposes, liquids are considered incompressible. In other words, an increase in fluid pressure is accompanied by a negligible reduction in volume.

Front 15

If a fluid pressure is 800 psi in 1/2-inch line supplying an actuation cylinder with a piston area of 10 square inches, the force exerted on the piston will be

Back 15

8,000 pounds

Hint 15

The size of the supply line has no effect on the answer to this problem. Simply apply Pascal's law which is force equals pressure times area. This force exerted on the piston is 8000 pounds (800 psi×10 square inches= 8,000 pounds).

Front 16

Which statement concerning heat and/or temperature is true?

Back 16

Temperature is a measure of kinetic energy of the molecules of any substance

Hint 16

He is a form of energy that causes molecular agitation within a material. The amount of agitation is measured by temperature. The temperature at which molecular motion stops is known as absolute zero.

Front 17

If both of volume and the absolute temperature of a confined gas are doubled, the pressure will

Back 17

Not change

Hint 17

The relationship between volume, temperature, and pressure of a confined gas is described by the general gas law. If both the volume and the absolute temperature are doubled, their effects cancel out and the pressure remains constant.

Front 18

if a double acting actuating cylinder is a 3000 PSI system has a piston with the surface area of 3 square inches on the extension side, and the road with a cross section area of 1 square inch attached to the piston on the other side, approximately how much force will the actuator be able to produce when retracting?

Back 18

6,000 pounds

Hint 18

To determine the force a hydraulic cylinder produces, multiply the piston area by the applied force. In this example, the piston area is 3 square inches on the extension side. However, the road on the retraction side reduces the piston area by one square inch, to 2 square inches. Multiply the applied force of 3000 pounds per square inch by 2 square inches to obtain the result force of 6000 pounds.

Front 19

Which condition is the actual amount of water vapor in a mixture of air and water?

Back 19

Absolute humidity

Hint 19

The actual amount of water vapor in a mixture of air and water is known as absolute humidity. relative humidity is the ratio of the amount of water vapor present in the atmosphere to the amount that would be present if the air was saturated. Dew point is the temperature to which the air must be cooled to become saturated.

Front 20

Which will wait the least?

1. 98 parts of dry air and 2 parts of water vapor.

2. 35 parts of dry air and 65 parts of water vapor.

3. 50 parts of dry air and 50 parts of water vapor.

Back 20

35 parts of dry air and 65 parts of water vapor.

Hint 20

Humid air at a given temperature pressure is lighter and right there at the same temperature pressure. Therefore, the choice with the greatest portion of water vapor weighs the least.

Front 21

If all, or significant part of a stall strip is missing on an airplane wing, a likely result will be

Back 21

asymmetrical lateral control at or near stall angles of attack.

Hint 21

Estas trip is a small which attached to a wings leading edge that causes the inboard portion of the wing to stop before the outboard portion. This allows the ailerons to maintain effectiveness up to the point of full stall. If part of a stall strip is missing, asymmetrical aileron control will result at or near stall angles of attack.

Front 22

Which is the ratio of the water vapor actually present in the atmosphere to the amount that would be present if the air were saturated at the prevailing temperature and pressure?

Back 22

Relative humidity

Hint 22

Relative humidity is the ratio of the amount of water vapor actually present in the atmosphere to the amount that would be present if the air were saturated at the prevailing temperature and pressure. Absolute humidity is the actual amount of water vapor in a mixture of air and water, and dewpoint is the temperature to which the air must be cooled to become saturated.

Front 23

Which atmospheric conditions will cause the true landing speed of an aircraft to be the greatest?

Back 23

High temperature with high humidity.

Hint 23

True airspeed (TAS) represents the true speed of an airplane through the air. As air temperature and humidity increases, the density of the air decreases. Therefore, high temperature with high humidity will cause an aircraft's landing speed to be the greatest.

Front 24

What is absolute humidity?

Back 24

The actual amount of the water vapor in a mixture of air and water.

Hint 24

Absolute humidity is the actual amount of water vapor present in a mixture of air and water. it is usually measured in grams per cubic meter or pounds per cubic feet. dew point is the temperature to which humid air must be cooled at a constant pressure to become saturated, whereas the ratio of the water vapor actually present in the atmosphere to the amount that would be present if the air were saturated at the prevailing temperature and the pressure is relative humidity.

Front 25

The temperature to which humid air must be cooled at the constant pressure to become saturated is called

Back 25

Dew point.

Hint 25

Dew point is the temperature to which humid air must be cold at the constant pressure to become saturated.

Front 26

The purpose of an aircraft wing dihedral is to

Back 26

Increase lateral stability.

Hint 26

Lateral stability, or roll stability, is increased through the use of dihedral. In other words, the wings on either side of the plane join the fuselage to form the slight "V" called the dihedral.

Front 27

Aspect ratio of a wing is defined as the ratio of the

Back 27

Wingspan to the mean chord.

Hint 27

A wing's aspect ratio is the ratio of the wing span to the average, or mean, chord.

Front 28

A wing with a very high aspect ratio, in comparison with the low aspect ratio, will have

Back 28

A low stall speed.

Hint 28

A wing with a high aspect ratio has low wing loading and, therefore, stalls at a lower speed.

Front 29

An increase in the speed at which an airfoil passes through the air increases lift because

Back 29

The increased speed of the air flow creates a greater pressure differential between the upper and lower surfaces.

Hint 29

The faster an airfoil moves through the air, the greater the pressure differential between the upper and lower surfaces. The greater the pressure differential, the greater the lift.

Front 30

The purpose of stall strips on airplane wings is to

Back 30

Ensure that the wing root areas stall first.

Hint 30

Stall strips are often installed on the leading edge in the wing root area to help induce a separation of airflow, thus producing a stall. This aids in retaining lift over the outboards ends of the wings so that aileron control is still available during initial onset of an aerodynamic stall.

Front 31

The speed of sound in the atmosphere is most affected by various and which of the following?

1. Sound frequency(cps).

2. Ambient temperature.

3. Barometric pressure.

Back 31

2

Hint 31

The speed of sound in the atmosphere varies with temperature. As the temperature decreases the speed of sound also decreases, and as temperature increases the speed of sound increases.