Exercises: Potential and Kinetic Energy and Energy Conservation
Define kinetic energy and gravitational potential energy. Give one everyday example of each.
Define kinetic energy and gravitational potential energy. Give one everyday example of each.
Classify each as mainly gravitational potential, elastic potential, chemical potential, or kinetic energy: (a) a stretched rubber band, (b) a bowl of pasta, (c) a book…
Classify each as mainly gravitational potential, elastic potential, chemical potential, or kinetic energy: (a) a stretched rubber band, (b) a bowl of pasta, (c) a book on a high shelf, (d) a cyclist riding down a street.
Sofia says, "Energy is used up when a ball stops rolling." Is she correct? State the law of conservation of energy and say where the ball's energy goes.
Sofia says, "Energy is used up when a ball stops rolling." Is she correct? State the law of conservation of energy and say where the ball's energy goes.
A roller coaster car is pulled to the top of the first hill and stops for a moment. Then it rolls down. Describe how its gravitational potential energy and kinetic…
A roller coaster car is pulled to the top of the first hill and stops for a moment. Then it rolls down. Describe how its gravitational potential energy and kinetic energy change as it moves from the top to the bottom of the hill. Say what happens to the total energy if friction is very small.
Trace the energy transformations in a simple circuit: a battery is connected to a light bulb. Name the type of energy at each stage (the battery, the moving charges, and…
Trace the energy transformations in a simple circuit: a battery is connected to a light bulb. Name the type of energy at each stage (the battery, the moving charges, and the light and heat given off by the bulb). Explain why the total amount of energy stays the same.
Aaliyah draws a food web in which grass is eaten by a grasshopper, the grasshopper is eaten by a frog, and the frog is eaten by a hawk. Describe how energy from the Sun…
Aaliyah draws a food web in which grass is eaten by a grasshopper, the grasshopper is eaten by a frog, and the frog is eaten by a hawk. Describe how energy from the Sun is transformed and transferred along this food web. Explain what happens to the energy that is not stored in each organism's body.
A $0.5\ \text{kg}$ ball is dropped from the top of a ramp. Its energy is measured at three points, in joules (J): | Point | Gravitational potential energy (J) | Kinetic…
A $0.5\ \text{kg}$ ball is dropped from the top of a ramp. Its energy is measured at three points, in joules (J):
| Point | Gravitational potential energy (J) | Kinetic energy (J) | Thermal energy from friction (J) |
|---|---|---|---|
| Top | 10 | 0 | 0 |
| Middle | 6 | 3 | ? |
| Bottom | 0 | 8 | ? |
(a) Calculate the missing thermal energy values. (b) Calculate the total energy at each point and use your results to explain whether energy is conserved. (c) Explain why the ball's kinetic energy at the bottom is less than $10\ \text{J}$.
Chloe compares three systems: a plant doing photosynthesis, a wind-up toy, and a swing at an amusement park. For each system, identify one form of potential energy and…
Chloe compares three systems: a plant doing photosynthesis, a wind-up toy, and a swing at an amusement park. For each system, identify one form of potential energy and one transformation that occurs. Then compare how the gravitational, elastic, and chemical potential energies are alike and different from kinetic energy, and explain how energy is conserved in at least one of the systems.