Final answer:
To safely use a hand truck, inspect for loose screws, damages, and worn straps. Mechanics increase leverage with a pipe over a wrench handle to remove tight bolts, which helps to apply more torque but risks breaking the bolt.
Step-by-step explanation:
Before using a hand truck, you should inspect the framework for all of the above: Loose bolts or screws, damaged or bent parts, and worn or frayed straps. Each of these could indicate potential failure points which may lead to the hand truck malfunctioning or breaking while in use, potentially leading to injury or damage to the materials being transported.
Effect of Leverage on Tight Bolts:
Mechanics sometimes put a length of pipe over the handle of a wrench when trying to remove a very tight bolt. This practice effectively increases the leverage that can be applied to the bolt. Leverage is the mechanical advantage gained by using a tool to multiply the force applied to another object. By adding a pipe over the handle of the wrench, the mechanic increases the distance from the pivot point where the force is applied, thereby increasing the torque. More torque can loosen tighter bolts with less force exerted by the person. However, this increased force must be used with caution, as it can potentially break the bolt or damage the tool if overexerted.