ASVAB Mechanical Comprehension Practice Test 624850 Results

Your Results Global Average
Questions 5 5
Correct 0 3.52
Score 0% 70%

Review

1 If the green arrow in this diagram represents 1050 ft⋅lb of work, how far will the box move if it weighs 210 pounds?
72% Answer Correctly
420 ft.
0 ft.
5 ft.
42 ft.

Solution
The Law of Work states that the work put into a machine is equal to the work received from the machine under ideal conditions. In equation form, that's:

Win = Wout
Feffort x deffort = Fresistance x dresistance

In this problem, the effort work is 1050 ft⋅lb and the resistance force is 210 lbs. and we need to calculate the resistance distance:

Win = Fresistance x dresistance
1050 ft⋅lb = 210 lbs. x dresistance
dresistance = \( \frac{1050ft⋅lb}{210 lbs.} \) = 5 ft.


2

What defines the mechanical advantage of a first class lever?

65% Answer Correctly

position of the fulcrum

output force 

output distance

input force


Solution

A first-class lever is used to increase force or distance while changing the direction of the force. The lever pivots on a fulcrum and, when a force is applied to the lever at one side of the fulcrum, the other end moves in the opposite direction. The position of the fulcrum also defines the mechanical advantage of the lever. If the fulcrum is closer to the force being applied, the load can be moved a greater distance at the expense of requiring a greater input force. If the fulcrum is closer to the load, less force is required but the force must be applied over a longer distance. An example of a first-class lever is a seesaw / teeter-totter.


3

Which of the following will increase the mechanical advantage of this inclined plane?

59% Answer Correctly

increase the force acting at the blue arrow

shorten the ramp

lengthen the ramp

lower the force acting at the blue arrow


Solution

The mechanical advantage (MA) of an inclined plane is the effort distance divided by the resistance distance. In order to increase mechanical advantage, this ratio must increase which means making the effort distance longer and this can be accomplished by lengthening the length of the ramp.


4

A watt is the unit for which of the following?

71% Answer Correctly

power

work

energy

mechanical advantage


Solution

Power is the rate at which work is done, P = w/t, or work per unit time. The watt (W) is the unit for power and is equal to 1 joule (or newton-meter) per second. Horsepower (hp) is another familiar unit of power used primarily for rating internal combustion engines. 1 hp equals 746 watts.


5

On Earth, acceleration due to gravity (g) is approximately __________. 

81% Answer Correctly

9.8 m/s2

6.67 x 10-11 m/s2

1 m/s2

1 m/s


Solution

Newton's Law of Univeral Gravitation defines the general formula for the attraction of gravity between two objects:  \(\vec{F_{g}} = { Gm_{1}m_{2} \over r^2}\) . In the specific case of an object falling toward Earth, the acceleration due to gravity (g) is approximately 9.8 m/s2