2. A student is investigating the strength of electromagnets she created using batteries, wire, and nails. She uses two different-sized nails and varies the number of coils of wire around the nail to determine how many paper clips each configuration can lift. She makes a data table of the results. The student hypothesizes that the number of coils has a cause-and-effect relationship on the strength of the magnetic devices she made. Which would be the best way for the student to test the devices to be sure that her hypothesis is accurate?

3. Neptune is known to have 14 moons, and their gravitational fields all interact as they orbit the distant planet. The image below shows eight of these moons. An astronomer wants to make a computer model to predict the effect of gravitational forces between Neptune and its moons and how they in turn affect their location as they move through their orbits. What data must be incorporated into the model that will best represent the gravitational forces between Neptune and its moons and the effect on their motion?

4. A team of engineers is developing a new waterslide for a theme park. The riders of the slide will climb several flights of steps to reach the top of the slide and will sit in a round inner tube as they slide down. The engineers are testing a computer simulation to measure the kinetic energy that the riders will have on the slide. The kinetic energy will be based on the potential, or stored, energy and will depend on mass and speed. The engineers want to develop a way to transfer the most kinetic energy to the riders to make their trip down the slide as fast as possible. Which of these solutions would increase the kinetic energy in the model slide?

5. A student rubs a comb on a cloth. She then holds the comb 30 centimeters above some small pieces of paper on a table, but the paper does not move. When the comb is moved closer to the paper, the paper moves through the air to the comb. Which statement explains why the paper does not move toward the comb when the comb is farther away?

6. An engineer is analyzing data to improve the design of a device that is being developed to move boxes up a ramp. The current device uses too much energy. The new device will transfer potential energy to kinetic energy to move the boxes. The device must be efficient and produce as much kinetic energy as possible. Which of the following explains why Device 3 best meets the design criteria?

7. A teacher sprinkles some iron shavings on a clear tray. She places two magnets in the shavings with the north ends facing each other. Based on the cause-and-effect relationship between the magnets, which phenomenon is the teacher modeling for her students?

8. A student makes a balloon cart to investigate how combined forces create motion. The student creates a simple cart by attaching wheels to a small piece of cardboard. The student attaches a straw with a balloon on one end so that any air coming out of the balloon flows in one direction. The student blows up the balloon, sets the cart on the tabletop, and lets go. Air flows out of the balloon and through the straw, but the cart does not move. Which of these explains why the car does not move?

9. Some friends are playing a game called croquet. One player uses their mallet to hit their ball into another ball. The first ball slows to a stop, and the second ball starts rolling. The friends come up with explanations to describe energy movement in the scenario. Which friend is correct?

10. Astronomers have been working with engineers on the design of a new tool. This tool will allow astronomers to better record observations and take measurements of asteroids in faraway locations. The tool must be lightweight, portable, and resistant to water, lightning, and other weather because it will be used outside. It will be powered by a standard battery, so it needs to be efficient and not use a lot of energy. It also needs to have a long run time. The engineers came up with four designs, which they tested and then recorded the results, shown in the table below. Which device would the astronomers most likely choose?

11. A student is developing and testing a new design of a model car on a model track. He makes a graph to show the results of his test. How can the student develop a solution to increase the kinetic energy of the model car?

12. A student is conducting an investigation to show how magnetic forces can act at a distance from an object. What can the student conclude from the data that he gathered in his investigation?