Free ASVAB Practice Tests

Blood is created in bone marrow and is made up of cells suspended in liquid plasma. Red blood cells carry oxygen, white blood cells fight infection, and platelets are cell fragments that allow blood to clot.

An acute angle measures less than 90°, a right angle measures 90°, and an obtuse angle measures more than 90°.

Voltage (V) is the electrical potential difference between two points. Electrons will flow as current from areas of high potential (concentration of electrons) to areas of low potential. Voltage and current are directly proportional in that the higher the voltage applied to a conductor the higher the current that will result.

Rulers are used to both measure distance and to draw straight lines. Tape measures are flexible rulers made from cloth or metal and are useful for measuring longer distances and in tighter spaces. Both rulers and tape measures provide similar accuracy, commonly down to \({1 \over 16}\) or \({1 \over 32}\) inch. A steel framing square is made up of a shorter ruler (tongue) and a longer ruler (blade) that meet at a 90° (right) angle. A framing square is often used by carpenters when framing stairs and roofs.

Resistance is opposition to the flow of current and is measured in ohms (Ω). One ohm is defined as the amount of resistance that will allow one ampere of current to flow if one volt of voltage is applied. As resistance increases, current decreases as resistance and current are inversely proportional.

Newton's second law of motion leads to the formula for acceleration which is a measure of the rate of change of velocity per unit time and, if you solve for positive acceleration, reveals how much net force is needed to overcome an object's mass.  The formula for acceleration is  \(\vec{a} = { \vec{F} \over m }\) or, solving for force,  \(\vec{F} = m\vec{a}\).

A half shaft is a drive axle that extends from a transaxle or differential to one of the drive wheels. There are two half shafts per drive axle, one for each wheel, each doing "half" the job.

The circumference of a circle is the distance around its perimeter and equals π (approx. 3.14159) x diameter: c = π d. The area of a circle is π x (radius)² : a = π r².

Micrometers provide accuracy to the thousandths of an inch and come in outside and inside varieties. An outside micrometer is used to measure outside thickness, such as the diameter of a bolt, while an inside micrometer is used to measure the inside dimension of an object, such as the diameter of the hole of a nut or the width of a channel.