Free ASVAB Practice Tests

Drag is friction that opposes movement through a fluid like liquid or air. The amount of drag depends on the shape and speed of the object with slower objects experiencing less drag than faster objects and more aerodynamic objects experiencing less drag than those with a large leading surface area.

Work is accomplished when force is applied to an object: W = Fd where F is force in newtons (N) and d is distance in meters (m). Thus, the more force that must be applied to move an object, the more work is done and the farther an object is moved by exerting force, the more work is done.

To solve this equation, repeatedly do the same thing to both sides of the equation until the variable is isolated on one side of the < sign and the answer on the other.

2z + 2 < 8 - 8z
2z < 8 - 8z - 2
2z + 8z < 8 - 2
10z < 6
z < \( \frac{6}{10} \)
z < \(\frac{3}{5}\)

The mechanical advantage (MA) of a block and tackle pulley is equal to the number of times the effort force changes direction. An easy way to count how many times the effort force changes direction is to count the number of ropes that support the resistance which, in this problem, is 8. With a MA of 8, a 190 lbs. effort force could lift 190 lbs. x 8 = 1520 lbs. resistance.

Wrenches are used with threaded fasteners like bolts and nuts. A bolt has external threads while a nut has internal threads and this thread pattern combination allows them to lock together and act as fasteners. Nuts come in a variety of configurations including wing nuts which provide appendages that allow tightening and loosening by hand, slotted nuts that use a cotter pin to lock the nut in place and prevent it from loosening, and lock nuts that also prevent loosening via nylon in their threads. Threads are identified by pitch which is the number of threads per inch.

Mechanical advantage (MA) is the ratio by which effort force relates to resistance force. If both forces are known, calculating MA is simply a matter of dividing resistance force by effort force:

MA = \( \frac{F_r}{F_e} \) = \( \frac{3 ft.}{10.0 ft.} \) = 0.3

In this case, the mechanical advantage is less than one meaning that each unit of effort force results in just 0.3 units of resistance force. However, a third class lever like this isn't designed to multiply force like a first class lever. A third class lever is designed to multiply distance and speed at the resistance by sacrificing force at the resistance. Different lever styles have different purposes and multiply forces in different ways.

Wood chisels are used to shape or smooth wood surfaces. They come in a variety of widths and can be used with hand power or tapped with a mallet when deeper cuts need to be made.

Collinear forces act along the same line of action, concurrent forces pass through a common point and coplanar forces act in a common plane.

Wood saws are categorized by their teeth shape and the number of teeth per inch (TPI). The higher the TPI of a saw the finer the cut it will make. Crosscut saws utilize knife-shaped teeth that cut across the grain of the wood while rip saws cut with the grain using chisel-shaped teeth that rip the wood cells apart as the cut is made. The kerf (slot) made by by a crosscut saw is much smoother than that made by a rip saw but a rip saw cuts much faster. Coping saws are a type of bow saw used to make detailed often curving cuts using replaceable blades with fine small teeth.