## Mechanical Comprehension Flash Card Set 442670

 Cards 10 Topics Boyle's Law, Force Lines of Action, Gear Ratio, Gear Trains, Kinetic Energy, Mechanics, Modulus of Elasticity, Structural Loads, Types of Simple Machines, Wheel and Axle

#### Study Guide

###### Boyle's Law

Boyle's law states that "for a fixed amount of an ideal gas kept at a fixed temperature, pressure and volume are inversely proportional". Expressed as a formula, that's $$\frac{P_1}{P_2} = \frac{V_2}{V_1}$$

###### Force Lines of Action

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

###### Gear Ratio

The mechanical advantage (amount of change in speed or torque) of connected gears is proportional to the number of teeth each gear has. Called gear ratio, it's the ratio of the number of teeth on the larger gear to the number of teeth on the smaller gear. For example, a gear with 12 teeth connected to a gear with 9 teeth would have a gear ratio of 4:3.

###### Gear Trains

Connected gears of different numbers of teeth are used together to change the rotational speed and torque of the input force. If the smaller gear drives the larger gear, the speed of rotation will be reduced and the torque will increase. If the larger gear drives the smaller gear, the speed of rotation will increase and the torque will be reduced.

###### Kinetic Energy

Kinetic energy is the energy of movement and is a function of the mass of an object and its speed: $$KE = {1 \over 2}mv^2$$ where m is mass in kilograms, v is speed in meters per second, and KE is in joules. The most impactful quantity to kinetic energy is velocity as an increase in mass increases KE linearly while an increase in speed increases KE exponentially.

###### Mechanics

Mechanics deals with motion and the forces that produce motion.

###### Modulus of Elasticity

The modulus of elasticity measures how much a material or structure will deflect under stress. Stretch modulus is longitudinal stretch (like stretching raw bread dough), shear modulus is longitudinal deflection (like the horizontal displacement of a stack of magzines when a heavy object is placed upon them), and bulk modulus is compression of volume (like the compression of a loaf of bread under a heavy can at the bottom of a grocery bag).