 For examples (a)–(f) below, match the event with the correct form of energy. | I. kinetic | II. gravitational potential | | III. elastic potential | IV. thermal | | V. electrical | VI. chemical |
- ___ Ice melts when placed in a cup of warm water.
- ___ Campers use a tank of propane gas on their trip.
- ___ A car travels down a level road at 25 m/s.
- ___ A bungee cord causes the jumper to bounce
upward.
- ___ The weightlifter raises the barbell above his
head.
- ___ A spark jumps from the girl’s finger to the
doorknob after she scuffs her feet on the wool
rug.
- Which of the following statements correctly describes the relationship between work and energy?
a. Energy is the stored ability to do work.
b. Work must be done in order for energy to be transferred between objects.
c. Work must be done in order for energy to change from one form to another.
d. All of the above.
- Are these statements about the spring constant true or false?
- The spring constant is a measure of the stiffness of the spring.
- The spring constant tells you how many newtons of force it takes to stretch the spring one meter.
- If a spring stretches easily, it will have a high spring constant.
- The spring constant of a spring varies with the amount of stretch or compression of the spring.
 The ErgoBot is a piece of dynamics demonstration equipment that displays in real time its displacement, velocity, and acceleration.
- Explain how you would use it to measure kinetic energy.
- Explain how you would use it to measure work done on it.
 The force of hot expanding gas from exploding gunpowder propels a cannonball out of the barrel of a cannon. How might the cannon be modified so that the cannonball leaves at a higher speed without increasing the amount of gunpowder used?
| | - Ask two friends if they can find the difference in the following two statements.
Statement 1: “A force that causes no change in an object’s position also does no work.”
Statement 2: “A force that does no work may not cause any change in an object’s position.”
Are both correct? In not, which is more correct? Write down their answers. How do they compare with your own answer?
- Is it possible to have very little power but use a lot of energy? How?
- Compare water flowing in a hose to electricity. Pressure in the pipe causes water to flow through the hose. What electrical quantity acts like pressure and causes electric current to flow?
- Which is the correct statement about a 12 V battery?
- 12 A of electric current can flow from the battery.
- Each ampere of electric current that flows carries 12 W of power.
- The battery contains 12 times as much stored energy as a 1 V battery.
- Which of the following energy flow diagrams might describe the path of the energy that powers the electric light in your classroom?
- nuclear energy > thermal energy > mechanical energy > electrical energy > light energy
- chemical energy > electrical energy > nuclear energy > light energy
- mechanical energy > chemical energy > electrical energy > thermal energy > light energy
- Ask two friends if they can find the difference in the following two statements.
Statement 1: “A runner with more power can expend energy more quickly to accelerate.”
Statement 2: “A runner with more energy uses more power when accelerating.”
Which one is more correct? Write down their answers. How do they compare with your own answer?
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