Free ASVAB Practice Tests | ASVAB Test Bank

Mechanical Comprehension

The radius of the axle is 3, the radius of the wheel is 4, and the blue box weighs 35 lbs. What is the effort force necessary to balance the load?

26.32 lbs.

The mechanical advantage of a wheel and axle is the input radius divided by the output radius:

MA = \( \frac{r_i}{r_o} \)

In this case, the input radius (where the effort force is being applied) is 4 and the output radius (where the resistance is being applied) is 3 for a mechanical advantage of \( \frac{4}{3} \) = 1.33

MA = \( \frac{load}{effort} \) so effort = \( \frac{load}{MA} \) = \( \frac{35 lbs.}{1.33} \) = 26.32 lbs.

Word Knowledge

Allison's painting met with plaudits from the critics, who had dismissed her earlier work.

kudos

Enthusiastic approval.

General Science

__________ is caused by a lack of Vitamin C.

scurvy

Scurvy is a difficiency disease caused by a lack of Vitamin C in the diet.

Arithmetic Reasoning

The total water usage for a city is 50,000 gallons each day. Of that total, 32% is for personal use and 59% is for industrial use. How many more gallons of water each day is consumed for industrial use over personal use?

13,500

59% of the water consumption is industrial use and 32% is personal use so (59% - 32%) = 27% more water is used for industrial purposes. 50,000 gallons are consumed daily so industry consumes \( \frac{27}{100} \) x 50,000 gallons = 13,500 gallons.

Mechanical Comprehension

If the green box is 8 ft. from the fulcrum and a certain force applied 7 ft. from the fulcrum at the blue arrow balances the lever, what is the mechanical advantage?

0.88

Because this lever is in equilibrium, we know that the effort force at the blue arrow is equal to the resistance weight of the green box. For a lever that's in equilibrium, one method of calculating mechanical advantage (MA) is to divide the length of the effort arm (E_a) by the length of the resistance arm (R_a):

MA = \( \frac{E_a}{R_a} \) = \( \frac{7 ft.}{8 ft.} \) = 0.88

When a lever is in equilibrium, the torque from the effort and the resistance are equal. The equation for equilibrium is R_ad_a = R_bd_b where a and b are the two points at which effort/resistance is being applied to the lever.

In this problem, R_a and R_b are such that the lever is in equilibrium meaning that some multiple of the weight of the green box is being applied at the blue arrow. For a lever, this multiple is a function of the ratio of the distances of the box and the arrow from the fulcrum. That's why, for a lever in equilibrium, only the distances from the fulcrum are necessary to calculate mechanical advantage.

If the lever were not in equilibrium, you would first have to calculate the forces and distances necessary to put it in equilibrium and then divide E_a by R_a to get the mechanical advantage.

Word Knowledge

Sadie's cowboy hat was incongruous with her black cocktail dress.

inappropriate

Not harmonious, incompatible.

General Science

During digestion, after proteins are broken down where does the undigested food go next?

small intestine

Food is mixed with gastric acid and pepsin in the stomach to help break down protein.

Automotive Information

Which engine stroke starts with the piston at top dead center?

intake stroke

The four-stroke piston cycle of internal combustion engines starts with the piston at top of the cylinder head (top dead center or TDC) during the intake stroke. The piston moves downward in the cylinder creating a vacuum that pulls an air-fuel mix into the combustion chamber through the now open intake valve.

Word Knowledge

Beneficial most nearly means:

advantageous

Helpful.

Shop Information

Inside and outside micrometers measure inside and outside:

diameters

Micrometers measure the diameter of cylindrical objects. Outside micrometers measure the external diameter of cylinders and inside micrometers measure the internal diameter of the cylinder's hole.