Download Physical Science – Ch. 5 – Energy Study Guide ANSWERS

Physical Science – Ch. 5 – Energy Study Guide ANSWERS
1. Distinguish between kinetic and potential energy. (Definitions)
Kinetic = energy of a moving object, energy in motion
Potential = stored energy, has the “potential” to do work
2. Calculate kinetic energy. (Equation)
KE = ½ m v2
3. Describe different forms of potential energy. (Types)
Gravitational = energy an object has based on its position above the
surface of earth, (like a book on a shelf)
Chemical = energy stored in chemical bonds (food, our body, mentos
in diet coke)
Elastic = energy stored in something that can be stretched or
compressed (rubber bands)
4. Calculate gravitational potential energy. (Equation)
GPE = 9.8mh
mgh
PE = weight x height
5. Describe how energy can be transformed from one form to another.
Solar panel on a car (Radiant/light  mechanical)
Gasoline into a car (Chemical potential  thermal  mechanical)
Radiant (light), mechanical, chemical potential, thermal (heat),
electrical, elastic potential, gravitational potential, kinetic,
6. Explain how the mechanical energy of system is the sum of the potential and the kinetic
energies.
Mechanical = energy due to the position and motion of an object or
objects in a system
Total potential and kinetic energies in a system
Transfers energy between potential and kinetic and back
7. Discuss the law of conservation of energy.
Energy cannot be created or destroyed, changes forms
Total energy remains constant
8. Define energy.
Ability to do work or cause a change
9. Relationship among the factors of PE
PE = mgh
Increase mass/height = increases PE
Decrease mass/height = decreases PE
10. Relationship among the factors of KE
KE = ½ mv2
Increase mass/velocity = increases KE
Decrease mass/velocity = decreases KE
11. Energy transfer while on a playground swing
Potential, kinetic, thermal/heat
GPE is greatest at peak of path, KE is lowest
KE is greatest at lowest point of path, GPE is lowest
12. Energy transfer between the Sun and Earth
Radiant/light comes to the Earth and heats it up, energy is stored in
plants, provides light to Earth and the Moon
13. Calories
Energy stored in food, chemical potential
1 Calorie = 4184 Joules
Fat, protein, and carbohydrates all contribute to Calories
SI Unit for Energy = Joule