Free ASVAB Practice Tests

The perimeter of a triangle is the sum of the lengths of its sides:

p = x + y + z
p = 12cm + 9cm + 9cm = 30cm

Insulators have valence shells that are more than half full of electrons and, as such, are tightly bound to the nucleus and difficult to move from one atom to another.

Capacitors store electricity and are used in circuits as temporary batteries. Capacitors are charged by DC current (AC current passes through a capacitor) and that stored charge can later be dissipated into the circuit as needed. Capacitors are often used to maintain power within a system when it is disconnected from its primary power source or to smooth out or filter voltage within a circuit.

Cylinders act as a guide for the pistons that translate the heat energy of combustion into the mechanical energy necessary to move a vehicle. Piston rings seal the piston to the cylinder to contain combustion gases and also regulate the oil distribution between the piston and cylinder wall. A cylinder head closes in the top of the cylinder forming the combustion chamber which is sealed by a head gasket (head). The head provides space for air and fuel intake valves, exhaust valves, and mounts for spark plugs and fuel injectors.

The first step to solve a quadratic expression that's not set to zero is to solve the equation so that it is set to zero:

a² + 6a - 13 = -a + 5
a² + 6a - 13 - 5 = -a
a² + 6a + a - 18 = 0
a² + 7a - 18 = 0

Next, factor the quadratic equation:

a² + 7a - 18 = 0
(a - 2)(a + 9) = 0

For this expression to be true, the left side of the expression must equal zero. Therefore, either (a - 2) or (a + 9) must equal zero:

If (a - 2) = 0, a must equal 2
If (a + 9) = 0, a must equal -9

So the solution is that a = 2 or -9

Brakes utlize friction to slow vehicle tires. Drum brakes employ a cast iron drum that roates with the vehicle axle. When hydraulic pressure is applied to the brake assemblies at the wheels, internal pistons expand and push brake shoes outward into contact with the brake drum slowing the rotation of the axle. More powerful disc brakes operate by pinching a rotating disc betweeen two brake pads and allow for a larger surface area to contact the disc, provide more force, and are more easily cooled.

A series circuit has only one path for current to flow. In a series circuit, current (I) is the same throughout the circuit and is equal to the total voltage (V) applied to the circuit divided by the total resistance (R) of the loads in the circuit. The sum of the voltage drops across each resistor in the circuit will equal the total voltage applied to the circuit.

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.

A chisel has a long sharp edge and is used, often in conjunction with a hammer, for cutting. In woodworking, chisels are used to remove large sections of wood to create the initial shape of a design. In metalworking, chisels are used to remove waste metal when a smooth finish is not required.