Let's analyze each question and determine the correct answer.
12. A squirrel standing on a branch rolls an acorn toward a hole in the tree. To determine how the potential energy of the acorn changes in relation to the earth, the position of what two objects must be considered?
- The potential energy of an object is determined by its height relative to a reference point (in this case, the earth). The acorn's potential energy changes based on its height above the ground (earth).
- C) The position of the acorn and the earth is the correct answer.
13. Ellen drops a ball from a cliff. Which statement best describes the ball's energy as it falls from her hand?
- As the ball falls, its height (and thus its potential energy) decreases, while its speed increases, which means its kinetic energy is increasing.
- C) The ball's potential energy decreases while its kinetic energy increases. is the correct answer.
15. Mrs. Wilson is driving her car to the store. She drives on a street where the speed limit is 50 mph. Then she turns onto a street where the speed limit is 45 mph. What happens to the kinetic energy of her car?
- Kinetic energy is calculated using the formula \((KE = \frac{1}{2}mv^2)\). When the car slows down from 50 mph to 45 mph, its speed decreases, which leads to a decrease in kinetic energy.
- C) When she slows from 50 mph to 45 mph, the car’s kinetic energy decreases. is the correct answer.
16. Which object has kinetic energy?
- Kinetic energy is the energy of motion. A person running on the sidewalk is in motion.
- D) a person running on the sidewalk is the correct answer.
17. Which object has potential energy?
- Potential energy is the energy stored in an object due to its position or height. An acorn sitting on top of a roof has potential energy because of its height relative to the ground.
- D) an acorn sitting on top of a roof is the correct answer.
Let me know if you need more explanations or have additional questions!