## MECH ENERGY

The straight forward answer to ‘what is mechanical energy’ is that it is the sum of energy in a mechanical system. This energy includes both kinetic energy(energy of motion) and potential energy(stored energy).

Objects have mechanical energy if they are in motion and/or if they are at some position relative to a zero potential energy position. A few examples are: a moving car possesses mechanical energy due to its motion(kinetic energy) and a barbell lifted high above a weightlifter’s head possesses mechanical energy due to its vertical position above the ground(potential energy).

Kinetic energy is the energy of motion. An object that has motion, vertical or horizontal motion, has kinetic energy. There are many forms of kinetic energy: vibrational (the energy due to vibrational motion), rotational (the energy due to rotational motion), and translational (the energy due to motion from one location to another).

Potential energy is the energy stored in a body or in a system due to its position in a force field or its configuration. The standard unit of measure for energy and work is the joule. The term “potential energy” has been used since the 19th century.

Because of the different components of mechanical energy, it exists in every system in the universe. From a baseball being thrown to a brick falling off of a ledge, mechanical energy surrounds us.

Well, at the top of the hill, the car is pretty much stationary, so where has all its kinetic energy gone? The answer is that it has been converted to potential energy. As the car begins its descent on the other side of the hill, the potential energy begins to be converted back to kinetic energy, and the car gathers speed until it reaches the bottom of the hill. Back at the bottom, all the potential energy the car had at the top of the hill has been converted back into kinetic energy.

An object’s mechanical potential energy derives from work done by forces, and a label for a particular potential energy comes from the forces that are its source. For example, the roller coaster has potential energy because of the gravitational forces acting on it, so this is often called gravitational potential energy.

## About Mechanical Tools

### Classic Hand Tool Examples

Assembly and Adjustment Tool Examples

• Precision Ratcheting Screwdriver Set
• Multi-tool with Pliers

A ratcheting screwdriver set contains a screwdriver handle and multiple bits. It includes the familiar flat-head and Phillips bits, but it also provides more specialized drivers and bits, such as the hexagonal Allen bit and the six-lobed Star, along with the square-slotted Robertson bit.

Some older video game systems used tamper-proof drivers such as the Tri-wing. Tri-wing screw slots look a little like the three central rays of a car’s steering wheel. You sometimes see the two-pronged spanner bit in your ratcheting screwdriver set, used to prevent tampering with bathroom stall doors. Ratcheting screwdriver sets also include Posidriv screw bits, used to avoid “cam-out” or slippage from the slot of Phillip’s head screws, and the bow-tie-shaped clutch screw, which was initially used in automobiles between 1940 and 1960, as well as in travel trailers, as late as the 1970s.

Mechanical engineers often have to cut and strip wires, so most carry at least one multi-tool with pliers. This tool might also include a sharp tool for piercing sheet metal, a pair of mini scissors, and several flat-head or Phillips head drivers. This multitool allows the mechanical engineer to reattach broken, corroded or loose wires, to restore functionality.

Measurement Tool Examples

• Calipers
• Caster/Camber/Toe-in Tester

Calipers look a lot like a draftsman’s compass: that tool you slide a pencil into to draw circles in math class. Calipers have two legs instead of just the one, and they are curved. You use inward-curving calipers to measure outside diameters. The tips of each leg curve outward for measuring inside diameters.

Caster/Camber/Toe-in testers measure tire angles and help engineers align the steering on vehicles. All three of these tools ensure that vehicle performance stays “on spec” or within the recommended manufacturer’s specifications. Toe-in/Toe-out gauges have a bar long enough to measure between the center of the left and right tires, with a prong at each end of the bar that slips into the tread groove on each tire without penetrating or piercing it.

Camber measures the inward or outward angle of the tire and the pavement. Zero camber creates a 90-degree angle between the roadway and the center line of the tire. Engineers use an angle finder and a straight edge to determine and adjust that angle.

Caster measures the angles formed between the upper and lower ball joints. Zero camber is straight down through the tire to the ground. Leaning toward the back of the car creates positive caster while leaning toward the front creates negative caster. Adjusting caster reduces stress on the ball joints.

Diagnostic Tool Examples

• Dental mirror
• Ohmmeters
• Digital Force Gauges

The same mirror your dentist uses to see inside your mouth to examine the back side of your teeth can help diagnose problems with hard-to-reach parts in vehicles and devices. Oversize versions of that same mirror help investigators view the undersides of aircraft and delivery vehicles when you have no access to lifts, ramps or jack stands.

Digital force gauges measure compression and tension. Digital force gauges help ensure that springs provide the correct amount of shock absorption for vehicles.

Ohmmeters help electrical engineers test resistance. The name comes from the use of the Greek letter, Omega in calculus. Engineers use calculus to measure rates of change.

All of these tools, along with their digital counterparts, help mechanical engineers design more efficient devices. Without them, engineers could not adjust performance specifications, discover and repair failure points or produce precision machine tools and parts. This testing process includes destruction tests designed to help engineers decrease injuries and enhance product safety.

### Examples of Mechanical Engineering Tasks

• Designing Prosthetics
• Nanotechnology
• Calibrating precision machinery
• Shaping public policy by providing testimony about design specifications and the effects of substitutions on failure points and on margins of safety
• Studying the sociology of how mechanisms help people

## The Journey Begins

Thanks for joining me!

Good company in a journey makes the way seem shorter. — Izaak Walton