Free ASVAB Practice Tests

As an object falls, its potential energy is converted into kinetic energy. The principle of conservation of mechanical energy states that, as long as no other forces are applied, total mechanical energy (PE + KE) of the object will remain constant at all points in its descent.

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.

The work-energy theorem states that the work done by the sum of all forces acting on a particle equals the change in the kinetic energy of the particle. Simply put, work imparts kinetic energy to the matter upon which the work is being done.

Blood is categorized into four different types (A, B, AB, and O) based on the type of antigens found on the outside of the red blood cells. Additionally, each type can be negative or positive based on whether or not the cells have an antigen called the Rh factor.

An overcooled engine is less efficient. During the power stroke, combustion heat pushes down the piston. If too much of this heat is lost to the cooling system, the fuel might not combust completely and contaminate the engine's lubricating oil diminishing its lubricating ability. Incomplete combustion of fuel also negatively affects the engine's fuel efficiency and power output.

A cube is a rectangular solid box with a height (h), length (l), and width (w). The volume is h x l x w and the surface area is 2lw x 2wh + 2lh.

The absolute value is the positive magnitude of a particular number or variable and is indicated by two vertical lines: \(\left|-5\right| = 5\). In the case of a variable absolute value (\(\left|a\right| = 5\)) the value of a can be either positive or negative (a = -5 or a = 5).

Velocity and displacement are vector quantities which means each is fully described by both a magnitude and a direction.  In contrast, scalar quantities are quantities that are fully described by a magnitude only.  A variable indicating a vector quantity will often be shown with an arrow symbol:  \(\vec{v}\)

Simple magnets have two poles, north and south, and opposite poles attract each other (N attracts S, S attracts N). Likewise, the same pole of two magnets repel (N repels N, S repels S). The Earth has a magnetic field and North and South Poles which enables the use of a magnetic compass to determine direction.