Energy Unit Review

Unit 4: Energy Review

Ms. Meyers - Science 8

There are 2 categories of energy that we've learned about this unit.

• potential energy

• kinetic energy

We also learned about the subtypes of energy. We learned about 3 types of potential energy.

• gravitational potential energy

• elastic potential energy

• chemical potential energy

Multiple Choice

What factors affect the amount of gravitational potential energy an object has?

• mass and velocity

• mass and type of material

• mass and elevation

• volume and height

Multiple Choice

What are the factors that affect the amount of elastic potential energy an object has?

• mass and type of material

• type of material and rigidity

• type of material and velocity

• type of material, rigidity, and amount of deformation

We've also discussed the relationships between factors and amount of different types of potential energy in objects.

• (GPE, EPE, CPE)

Multiple Choice

Which of the following is the correct relationship between elevation and gravitational potential energy?

• as elevation decreases, GPE increases

• as elevation increases, GPE decreases

• as elevation increases, GPE increases

• as elevation increases, GPE is not affected

Multiple Choice

Which of the following is the correct relationship between rigidity and elastic potential energy?

• as rigidity increases,

  EPE decreases

• as rigidity decreases,

  EPE increases

• as rigidity changes, EPE is not affected

• as rigidity increases,

  EPE increases

Multiple Choice

Where is chemical potential energy stored?

• in the nucleus of the cell

• in the protons

• in the bonds between atoms

• in the nucleus of atoms

In addition to types of potential energy, we also learned the factors that affect the amount of kinetic energy an object has, as well as a couple different types of kinetic energy.

• thermal energy

• sound energy

Multiple Choice

What are the factors that affect the amount of kinetic energy?

• mass and volume

• mass and type of material

• volume and elevation

• mass and velocity

Multiple Choice

Which of the following would have more kinetic energy? (Hint: use the formula below to solve for each one, then choose your answer.)

$$KE=\frac{1}{2}mv^2$$  

• a 100kg person walking at 5 km/h

• a 50 kg person running at 10 km/h

Multiple Choice

What are the factors that affect the amount of thermal energy?

• mass and velocity

• mass and temperature

• type of material

  and mass

• velocity and volume

Multiple Choice

Which of the following would have more thermal energy?

• a 0.5 kg cup of coffee at 60^oC

• a 0.5 kg cup of coffee at 50^oC

Multiple Choice

Which of the following would have more thermal energy?

• a 0.5 kg cup of coffee at 60^oC

• a 1.0 kg cup of coffee at 60^oC

Energy Transformation (or conversions) is another topic we discussed.

• not to be confused with energy transfer

Multiple Choice

What is an energy transformation (or conversion)

• when energy leaves one object (or system) and moves to another object (or system)

• when energy changes from one type of energy to another type of energy

Multiple Select

Which of the following types of energy did the kinetic energy in the bouncing ball example convert to as the cart slowed and stopped?

• gravitational potential energy

• thermal energy

• sound energy

• elastic potential energy

Energy Transfer is one of the last topics we learned about in our Energy unit.

• not to be confused with energy transformation

Multiple Choice

What is energy transfer?

• when energy moves from one object (or system) to another object (or system)

• when energy changes from one type of energy into another type of energy

Poll

Was the kinetic energy in the bouncing ball example lost or conserved?

(Be prepared to discuss)

• The kinetic energy was lost because the ball slowed down and stopped, which left no kinetic energy in the ball.

• The kinetic energy was conserved because it didn't disappear, it just transformed into other types of energy and moved out of the ball and into the surroundings as other types of energy.

Finally, we discussed energy transformations and transfers in chemical reactions.

• endothermic reactions

• exothermic reactions

Multiple Choice

Which of the following is a reaction that releases thermal energy?

• endothermic reaction

• exothermic reaction

Multiple Choice

Which of the following causes thermal energy to be released in an exothermic reaction?

• the breaking of chemical bonds

• the formation of chemical bonds

Multiple Choice

Which is a reaction that absorbs thermal energy?

• endothermic reaction

• exothermic reaction

Multiple Choice

Which of the following causes thermal energy to be absorbed in an endothermic reaction?

• the breaking of chemical bonds

• the formation of chemical bonds

Multiple Choice

Which of the following energy transformations and transfers represents an endothermic reaction?

• chemical energy transforms into thermal energy and is released to the surroundings

• chemical energy transforms into thermal energy and is absorbed by the new chemical bonds

• thermal energy transforms into chemical energy and is released to the surroundings

• thermal energy transforms into chemical energy and is absorbed by the new chemical bonds

Multiple Choice

Which of the following energy transformations and transfers represents an exothermic reaction?

• chemical energy transforms into thermal energy and is released to the surroundings

• chemical energy transforms into thermal energy and is absorbed by the new chemical bonds

• thermal energy transforms into chemical energy and is released to the surroundings

• thermal energy transforms into chemical energy and is absorbed by the new chemical bonds