Types of Energy
What type of energy comes from the vibration of guitar strings?
Sound Energy
What type of energy does a stretched rubber band have?
Potential Energy (Elastic)
What does the law of conservation of energy tell us?
That energy cannot be created or destroyed, it is just transformed into other types of energy.
What are the three ways that heat is transferred?
Conduction, Convection, and Radiation
What force converts kinetic energy into thermal energy when you rub your hands together?
Friction
What kind of energy is contained within the nucleus of an atom?
Nuclear Energy
What kind of energy does a ball have when it is thrown in the air?
Both kinetic and potential energy. Kinetic due to its speed, and potential due to its height off the ground.
What energy transformations occur in a microwave?
Electrical → Radiant (microwaves) → Thermal (heating food)
Why does a tile floor feel colder on bare feet than carpeted floor, even if both are in the same room?
Tile is a good conductor and pulls heat away from your feet quickly, while carpet is an insulator and transfers heat more slowly.
When an object travels through the air, what is one way that energy is lost due to air resistance?
1. Through the object giving some of its kinetic energy to the air molecules when it pushes them out of the way.
2. Through thermal energy produced by friction between the air molecules and the object.
3. Through sound energy produced by the vibrations of the air molecules when they move.
What type of energy is kinetic while electrons are moving and potential when they are not?
Electrical Energy
What happens to the potential energy of a rollercoaster as it goes down a hill?
The potential energy gets converted into kinetic energy.
What energy transformations occur when you turn on a flashlight?
Chemical (battery) → Electrical → Radiant + Thermal (it produces both light and heat)
Why does the water in a hot tub stop feeling so hot after a few minutes?
As your skin heats up, it gets closer to the temperature of the water and less heat gets transferred.
A moving car suddenly slams on the brakes, coming to a stop. Where does most of the car’s kinetic energy go?
It is mostly turned into thermal energy due to friction between the wheels and the road. (Some of it is also turned into sound energy)
What type of energy is released when food is broken down in your body?
Chemical Energy
A falling rock has 0 J of kinetic energy and 1000 J of potential energy when it falls off a cliff. How much energy of each type will it have when it has fallen halfway down to the ground? (Assuming that no energy is lost)
500 J of kinetic energy and 500 J of potential energy
PE = mgh, so if no energy is lost its potential energy will be half when it is halfway down.
Because some of the mechanical energy is lost through transformations into other types of energy like heat and sound.
Why do metals feel colder than wood, even at the same temperature?
Metals conduct heat away from your hand faster than wood does.
A planet orbits a star without falling into it. What force is responsible, and what types of energy does it have?
A gravitation force keeps the planet orbiting the sun. It has both kinetic energy (due to its motion) and potential energy (due to its distance from the sun).
What type of energy comes to us from the stars?
Radiant Energy (light)
Describe how energy changes as a pendulum swings from its highest to lowest point.
Potential energy is highest at the top, converts to kinetic energy at the lowest point, then converts back to potential as it rises again.
In a nuclear power plant, this type of energy from uranium is used to produce this type of energy, which turns water into steam. The steam gains this type of energy as it moves and spins a turbine, converting it into this type of energy. Finally, the turbine drives a generator to produce this type of energy to provide power.
Nuclear → Thermal → Kinetic (rising steam) → Kinetic (spinning turbines) → Electrical
Why does black clothing absorb more heat than white clothing?
It absorbs more wavelengths of light, transferring more heat through radiation.
A metal paperclip is sitting on a table and pushed near a strong magnet. Suddenly, the paperclip starts moving on its own towards the magnet. What causes the paperclip to move, and how does its energy transform?
The magnet applies a force to the paperclip, pulling it towards the magnet. The paperclip has potential energy due to its distance from the magnet, which is converted into kinetic energy as it speeds up.