Definitions
The ability to do work.
Energy
Define electrical energy.
The energy associated with moving charged particles.
Define power.
The amount of work done each second.
The equation for work.
W = F * D
In machines work output is always _____ than work input.
LESS
Define potential energy.
Energy that is stored as a result of position or shape.
Give an example of electromagnetic energy.
Sun, Radio waves, Microwaves, Infrared radiation, Light, UV light, X-rays, Gamma radiation
The acceleration due to gravity (the actual value).
9.8 m / s2
The equation for potential energy.
PE = m * g * h
The reason that we repeat an experimental process multiple times. (What are we trying to reduce?)
Experimental error
Define chemical energy.
The energy stored in the chemical bonds of the molecules that make up a substance.
The actual mechanical advantage of machine is always less than its ideal mechanical advantage. Explain why.
The presence of friction.
Daily Double - what amount would you like to wager?
Explain horsepower!
Math bonus: what is the general equation of a line?
y = mx + b
Friction causes kinetic energy to be converted into _____. [Hint - it's a type of energy.]
Thermal energy!
Define mechanical energy.
The sum of an object’s potential energy and kinetic energy.
If the speed of an object doubles, this happens to its kinetic energy.
It quadruples (because KE = m * v2).
So if v=2, it would be "4" but if v is doubled and v=4, then v2 = 16. And 16 is 4 times or quadruple the amount of 4.
There are six types (categories) of simple machines. List 3.
Inclined plane, wedge, screw, lever, wheel and axle, pulley.
The equation for kinetic energy.
KE= 1/2 * m * v2
EACH team has 90 seconds. All correct answers receive $400.
If you exert force of 500N to walk 4.0m up a flight of stairs in 4.0 seconds, how much power do you use? [Hint: W = F x d]
P = W/t or P = (W x d) / t
Or
(500.0 N)(4.0)m / 4.0s = 500.0 J/s = 500.0 Watts
Define thermal energy.
The total kinetic energy of the moving atoms and molecules of an object.
A small meteoroid is approaching the earth. (We’re all gonna die!) It has a mass of 120 kg and speed of 10.0 km/s. How much kinetic energy does the meteor oil have?
6000 J
[mass = 120.0 kg, v = 10.0 m/s]
KE = 1/2 x m x v2
KE = 1/2 (120kg) (10m/s)2
KE = 6,000 J of kinetic energy
Name one Bible verse that relates to anything we've discussed today (can't be our devotion verse).
You are brilliant students!
Explain the law of conservation of energy.
Energy is not created or destroyed but instead is transferred from one object to another.
A machine has a 75% efficiency. What happens to 75% of the work put INTO the machine and what happens (specifically) to the 25%?
75% become work OUTPUT and 25% is lost to FRICTION