Unit 5 Lesson 2.
1. A city gets its electricity from a dam, where water is stored in a reservoir. How does the water provide the city with its power?(1 point)
Potential energy in the water becomes kinetic energy as it moves through turbines, which turn kinetic energy into mechanical energy that spins a generator, which changes mechanical energy into electricity.
2. An acorn rolls off a roof and falls to the ground. Which statement best describes the change in energy?(1 point)
The acorn’s potential energy decreases as its kinetic energy increases.
3. An airplane carries 320 passengers from Phoenix to Los Angeles flying at an average speed of 490 miles per hour. On the return flight, the plane carries 164 passengers and travels at the same average speed. What happens to the plane’s kinetic energy?(1 point)
On the return flight, the plane has less kinetic energy.
4. A racehorse is running at 42 miles per hour, equivalent to 18.8 meters per second. The horse and its jockey have a combined mass of 512 kilograms. How much kinetic energy do they have?
KE = 1/2 mv^2 (1 point)
90,480.6 J
5. Which object has kinetic energy?(1 point)
balloon rising in the sky
6. Mr. Starr pushed a cart full of groceries to his car. After emptying the cart, he pushed it back to the store. He pushed the cart at a speed of 2 meters per second each way. Which is the best prediction?(1 point)
When it was empty, the cart had less kinetic energy.
7. A student fires a toy rocket into the sky. When does the rocket have the most potential energy?(1 point)
when the rocket reaches its highest point
8. What is the best description of one billiard ball hitting a second billiard ball?(1 point)
Most of the kinetic energy in the first ball is transferred to the second ball.
9. A roller-coaster car is at the top of a hill. The car and its passengers have a combined mass of 1,088 kilograms. If the hill is 62 meters tall, how much potential energy does the car have? PE = mgh (1 point)
661,068.8 J
10. A roller-coaster is at the top of a 62-meter hill. The car and its passengers have a total mass of 1,088 kilograms. By the time the car reaches the bottom of the hill, its speed is 74 miles per hour (33 meters per second). How much kinetic energy does the car have at the bottom of the hill?
KE = 1/2mv^2
(1 point)
592,416 J
11. A diagram is drawn showing a swing set with a swing pulled backward prior to release. The diagram shows how the swing will move forward and then backward after it is initially released. At which point in the diagram is all of the energy gravitational potential energy?(1 point)
when the swing is pulled back prior to release
12. In 1–2 sentences, describe how a student could use collaborative learning to investigate potential energy.(2 points)
What is potential energy, The energy that an object has as a result of its position in relation to another object is defined as potential energy.standing at the top of a stairwell has more potential energy than standing at the bottom. Because gravity can pull you down while doing work.
13. In 1–2 sentences, explain how you could find the kinetic energy of a baseball when it hits a window.(2 points)
It gos straight thru the glass and slows dawn.
15/15 Points Earned