Work & Power
This is the unit used to measure Power.
What is watt?
True or False: An object's kinetic energy is not related to it's mass
False
Name the two nuclear reactions we talked about and where you can see each of them happening.
Fusion - the sun
Fission - nuclear power plant
DAILY DOUBLE
This is the term used to describe energy's tendency to be randomly spread out and disordered.
Marcus carries a heavy box of detergent around the store. Is any work done on the box in this scenario? Why or why not?
No work. Force and motion have to be in the same direction for work to be done.
A scared snowboarder at the top of a hill is standing still. Despite being immobile, he still has this type of energy.
What is gravitation potential energy?
Electrical energy comes from (blank).
Chemical energy comes from (blank).
charges
bonds
What is the law of conservation of energy? Provide an example
Energy cannot be created or destroyed.
It took 2.28 kJ of energy to move an object 12 meters. How large was the force necessary to do this work?
190 N of force
What is the difference between gravitational and elastic potential energy?
Gravitational depends on height, elastic depends on shape.
These are the only two types of energy we discussed that are purely potential energy.
Nuclear and Chemical energy
This is the difference between energy transfer and energy transformation.
Energy will change forms in a transformation as it goes from one body to another.
A transfer is when energy moves from one body to another, without changing forms.
An experimental 28 W lightbulb receives 336 J of energy. How long will this power the lightbulb?
12 seconds
An astronaut has a weight of 40 N while standing on a cliff on the moon. If he has a potential energy of 7.6 kJ, how tall is the cliff?
190 m
Describe two ways in which a tray at rest on a table has energy.
Mechanical potential energy depends on the tray's height from the ground.
Thermal energy accounts for the kinetic and potential energy of the particles/atoms of the tray
After a train zooms by at high speeds, the rails feel hot to touch. Describe the energy transformation that took place.
Friction between the wheels and the rails transformed mechanical kinetic energy to thermal energy.
Use all of the following words in a single cogent sentence: energy, force, motion, work. (One chance only and the sentence has to make sense scientifically and grammatically).
answers vary
Imagine a 100 kg car traveling at 10 m/s. How much more kinetic energy does the car gain if you doubled its speed?
Original KE = .5 * 100 kg * (10 m/s)2 = 5,000 J
Double speed = .5 * 100 kg * (20 m/s)2 = 20,000 J
ANSWER = 15,000 J more
Name 5 different types of electromagnetic radiation.
Radio, Micro, Infrared, Visible light, Ultraviolet, X-ray, Gamma
Describe in detail the changes in kinetic and potential energy when an apple falls from a tree.
Initially the apple only has PE. As it falls, the PE continuously transforms to more and more KE. Some energy is lost along the way to friction from air resistance as thermal energy. When the apple lands, it stops moving, thus has no more KE. The energy has transformed into thermal energy of the apple, the ground, and the air.