WORK
What is the equation for work?
W = Fd
What is the equation for power?
P = W/t
Mechanical Energy includes what two forms of energy?
KE and PE
What does conservation mean?
It means something is unchanging
What shape is the earth?
a sphere
Describe work in TWO different ways.
- Force applied over a certain displacement
- The transfer of energy
Describe power in TWO different ways
- The rate of energy transfer
- How quickly work is done
What is conserved when friction is absent?
Mechanical Energy
Energy cannot be __________________ or destroyed. It can be _______________________ from one form into another.
Created, Transformed
This planet, known as the "Red Planet," is home to the largest volcano in the solar system, Olympus Mons.
Mars
How much work does a weightlifter do to lift a 200kg barbell 5 meters overhead? Include units.
10,000 Joules
What are the units for power? Give me both the unit and what it is derived from.
Watts
Joules / Second
If a skier falling down a mountain has 1,500J at the top of the mountain. How much KE and PE does he have halfway down the mountain?
750J of PE
750J of KE
In a swinging pendulum, when is KE the greatest? PE? Disregarding friction, does ME change during the swing?
KE - bottom
PE - top on both sides
ME never changes
This fundamental force, the weakest of the four, governs the attraction between masses.
Gravity
Describe how a machine makes work "easier"
Trades distance for force
What are the two ways we calculate efficiency?
Useful Energy out / Energy in
Actual MA / Theoretical MA
How do we determine each type if lever? How do we increase MA when using a lever?
Type 1 - fulcrum in the middle
Type 2 - Load in the middle
Type 3 - Effort in the middle
Move effort further from the fulcrum
Using conservation of energy, explain how we used gravitational potential energy to calculate the spring constant (k) in our lab with the jump toy.
PEg = PEe
Thus allowing us to single out variable k to solve for its value.
This marine mammal can sleep with one half of its brain awake to keep it safe from predators.
What is a dolphin?
What is the efficiency of a machine that requires 200 J of energy to do 30 J of work? ALSO describe efficiency using your own words.
15% efficient
Efficiency is how effectively energy is converted from one form to another without being wasted, typically as heat, friction, or other losses.
While using a pulley system, you notice that you are able to lift a 5,000gram mass with only 10 Newtons of force. What MA does this pulley system give you?
Effort = 10
Load = 50
MA = 5
Friction creates thermal energy.
The energy is not actually lost. It is just transformed into heat which is less useful energy.
This groundbreaking 1993 first-person shooter by id Software popularized multiplayer deathmatches.
What is Doom?