The picture below shows a pinwheel that Bobby has in his front yard. Often Bobby sees his pinwheel spinning, but other times it does not spin. Which statement best explains what makes his pinwheel spin?

Question

options:

A). The Sun heats up the pinwheel, causing it to turn.

B). The colors on the wheel repel one another, causing it to turn.

C). Energy from the ground shakes the wheel causing the pinwheel to move.

D). Energy from the wind pushes on the wheel causing the pinwheel to move.

Answer 1

The correct statement that best explains what makes Bobby's pinwheel spin is:

D). Energy from the wind pushes on the wheel causing the pinwheel to move.

Pinwheels typically spin when wind blows against them, as the force of the wind acts on the blades of the pinwheel, causing it to rotate.

Answer 2

Kim is upstairs, but walks downstairs to the kitchen for a snack. Which statement correctly describes the types of energy she has at the top of the stairs and as she walks down the stairs?

options:

A). kinetic energy at the top of the stairs; kinetic energy as she walks down

B). potential energy at the top of the stairs; potential energy as she walks down

C). potential energy at the top of the stairs; kinetic energy as she walks down

D). kinetic energy at the top of the stairs; potential energy as she walks down

Answer 3

The correct statement that describes the types of energy Kim has at the top of the stairs and as she walks down is:

C). potential energy at the top of the stairs; kinetic energy as she walks down.

At the top of the stairs, Kim has potential energy due to her height above the ground. As she walks down the stairs, her potential energy decreases, and her kinetic energy increases as she moves.

Answer 4

Rebecca climbs the ladder of a large water slide, waits her turn at the top, and then slides down the slide into a pool. Which answer best describes the energy changes during her time on the slide?

options:

A). kinetic → mechanical → potential

B). kinetic → potential → kinetic

C). potential → mechanical → kinetic

D). potential → kinetic → potential

Answer 5

The answer that best describes the energy changes during Rebecca's time on the water slide is:

D). potential → kinetic → potential.

1. Potential Energy: When Rebecca climbs the ladder to the top of the slide, she has gravitational potential energy due to her height.
2. Kinetic Energy: When she slides down, her potential energy is converted into kinetic energy as she accelerates down the slide.
3. Potential Energy: When she reaches the bottom of the slide and enters the pool, her kinetic energy will be converted back into potential energy as she comes to a stop or if she floats on the water surface (assuming the water level is higher than the pool's bottom).

So, the correct sequence is potential energy at the top, kinetic energy while sliding, and potential energy when coming to a stop.

Answer 6

If we don’t consider friction, what happens to the total mechanical energy as the pendulum swings from position A to position B?

options:

A). It is not conserved

B). It declines

C). It becomes greater.

D). It remains the same

Answer 7

If we don’t consider friction, the correct answer is:

D). It remains the same.

In an ideal pendulum scenario (without friction or air resistance), the total mechanical energy (the sum of potential energy and kinetic energy) is conserved as the pendulum swings. As the pendulum moves from position A (the highest point) to position B (the lowest point), potential energy is converted into kinetic energy, but the total mechanical energy remains constant.