Energy
(The Basics)
(The Basics)
What are the two main types of energy?
Kinetic and Potential Energy
What units are used for the following:
Potential Energy
Kinetic Energy
Mass
Height
Velocity
Ek: J
Ep: J
Mass: kg
Height: m
Velocity: m/s
What semiconductor is used in photovoltaic cells?
Silicon
What element is most commonly used in nuclear reactors?
If particles are moving fast what does that mean in terms of its thermal energy? What about its temperature?
The faster particles move the more thermal energy they have. The more thermal energy they have, the higher the temperature.
What does the Law of Conservation of Energy state?
Energy cannot be created nor destroyed, only transferred or transformed
Your friend has a mass of 70 kgs and bungee jumps from a height of 85 m above the surface of mars. Their gravitational potential energy is 22,015 J. What is the acceleration due to gravity on mars?
g = 3.7 m/s2
Give one way in which ATP is transformed in living tissues.
1. ATP -> mechanical kinetic energy when muscles contract
2. ATP -> chemical potential energy when new molecules are created
3. ATP -> electrical potential energy to send signals to nerve cells
Describe what a radioactive isotope is.
It is an isotope that has too many neutrons compared to protons causing it to have too much energy and becoming unstable.
If something has a high heat capacity would it heat up quickly or slowly? Would it cool down quickly or slowly?
It would heat up and cool down slowly because it takes more energy to change its temperature.
A shower is an example of what two types of energy?
Mechanical Kinetic Energy and Thermal Energy (could also say Sound)
Ms. Johel traded in Jimmy for a school bus that weighs 9,500,000 g. What is the kinetic energy of the school bus if it travels a distance of 50 kms in 52 mins?
Ek = 1,219,901 J
Describe the energy transformations for the following:
1. Campfire
2. Rubbing your hands together
3. Riding a bike
1. Chemical -> Thermal + Radiant
2. Mechanical Kinetic -> Thermal + Sound
3. Chemical -> Mechanical + Thermal
Describe what nuclear fission and fusion are.
Nuclear Fission: Large nucleus splits into two smaller nuclei
Nuclear Fusion: Two small nuclei combine/fuse together to form a larger nucleus
Describe what conductors and insulators are and give two examples for each.
Conductors - materials that heat can easily flow through ex. metals (silver, aluminum, gold, copper, etc)
Insulators - materials that heat cannot easily flow through ex. rubber, plastic, foam, wool, glass
Give an example of something in this room that has multiple types of energy.
Answers will vary.
A 4,200 kg roller coaster sits at the top of a 2000 cm hill. Calculate the potential energy.
What would be the velocity of the roller coaster going down the hill.
Ep = 823,200 J
Ek = 19.8 m/s
Give the reactants and products for photosynthesis and cellular respiration.
Photosynthesis:
Light Energy + Carbon Dioxide + Water -> Glucose + Oxygen
Cellular Respiration:
Glucose + Oxygen -> Carbon Dioxide + Water + ATP (energy)
Where does nuclear fission and fusion occur?
Nuclear Fission occurs in nuclear reactors
Nuclear Fusion occurs in the Sun and other stars
List the 3 types of heat transfer and give an example for each.
1. Conduction - a metal spoon in a hot soup
2. Convection - moving wind or ocean currents
3. Radiation - roasting a marshmallow
List the 5 types of Kinetic Energy and give an example for each.
1. Mechanical Kinetic - moving car, rolling ball
2. Radiant - sunlight, light bulb, TV, phone
3. Thermal - hot cup of coffee, iron, fire, toaster
4. Sound - alarm clock, radio, instrument
5. Electrical Kinetic - electrical outlet, charger
A bodybuilder lifts an 80,000 g barbell, holds it up for a second, and then drops it. The barbell reaches a velocity of 4.5 m/s before hitting the ground. How high did he lift the barbell?
Height = 1.03 m
Describe the energy transformation that allows us to perceive an image.
Light is absorbed by rhodopsin which is found in rod and cone cells in the retina. When rhodopsin absorbs light, electrons get excited. This then causes a nerve cell to send an electrical signal to the brain that carries the info. The brain then interprets the info and you perceive an image.
Complete the following nuclear equations.
Alpha: Californium
Beta: Dysprosium
Gamma: Uranium
Answer shown on board because Ms. Johel isn't tech savvy enough to show it on here :p
The specific heat capacity of ethanol is 2440 J/kgoC. A 276 g can of ethanol is chilled in the fridge and releases 8,686 J of energy. lf the ethanol has a temperature of 5.55 oC after chilling, what was the initial temperature?
Ti = 18.45 oC