Formulas & Units
What are the correct units for MASS?
grams (g) or kilograms (kg)
Present in an object that has the potential to move
Potential Energy
Transfer of thermal energy
Heat energy
An inclined plane wrapped around a cylinder. Ex. spiral staircase
Screw
For work to be done, there must be ______________
displacement!
What is the appropriate unit for energy?
[Hint: kinetic, potential, WORK]
Joule (J)
EM interactions
Electrical Energy
Gravitational Potential Energy depends on what 2 factors?
mass and height
Name the 2 types of pulleys
Fixed pulley (attached to something; only changes to the direction of force) and Movable pulley (free to move)
The unit for POWER
Watts
What is the formula for WORK?
Work=Force * Displacement
Energy that is stored in objects that are stretchy
Elastic Potential Energy
What is mechanical energy
sum of KE and PE
What is an example of a 2nd class lever?
wheelbarrow, crowbar, the handle of nail clippers, nutcrackers
A measure of how much a force acting on a object causes that object to ROTATE
Torque
This formula relates to motion of energy
Kinetic energy; 1/2mv2
States that energy can neither be created nor destroyed ....it can only be transferred from one form of energy to another.
Laws of Conservation of Energy
Thermal energy is an example kinetic energy. True or False
True! thermal energy is due to temperature, which comes from the motion of molecules
Ideal Machine efficiency is 100% and MA is 100%. Why does it not exist?
Friction! Due to Law of Conservation of Energy, energy will always be transferred.
22.5 N
Formula for efficiency
E=Work Output/Work Input
Lever
There is a bell at the top of a 180 m high tower. The bell is 190 kg. What is the potential energy of the bell?
335,160 J
What is the amount of useful work output of a 35% efficient bicycle if the amount of work input is 80 N-m?
28 N-m= Work Output
An 187,000 W engine can accelerate from rest to a top speed in 6 seconds. How much work did the engine do?
1,122,000 J