1.Two materials that can be scratched by an iron mail are ___, ___ 2.What is the substance that can be scratched by an iron nail but not a penny?
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The velocity of a car traveling in a straight line increases from 0 meters/second to 30meters/second in 8 seconds. what is the average acceleration of the car?

What is the difference between a solar cell and a solar panel

100 ! make you brainliest! asap pleaze hurry 1. which scientific theory explains that the universe originated from a small, densely packed space? 2. observations of space show that galaxies are moving away from us as observers on earth. how is this related to how the universe formed? 3. one force is responsible for holding together stars with planets, planets with moons, and stars in galaxies. what is this force? 4. as the solar system formed, most of its mass became concentrated in one part of it. what is that that part? 5. using the law of gravitation, explain why the moon orbits the earth and the planets orbit the sun. 6. many people think that summer is warmer because the earth is closer to the sun at that time of year. your experience with seasons has taught you this is not true. explain why. 7. if earth rotated on an axis that was not tilted, how would this affect the seasons? 8. does this show the geocentric or heliocentric idea of the solar system? explain the difference. 10. as fast as you can, name the planets in order from the sun. 11. as fast as you can, name the planets in order from smallest to largest. 12. as fast as you can, name the planets in order from least mass to most mass. hint: check your notes about the gravitational force on each planet compared with earth. name a unique trait about each planet in our solar system.