Name ______Period ______
Exercises 1.3
Show Work When Necessary
1. All planets orbit the Sun because of the force of gravity. Earth has a certain force keeping it in its orbit.
- If the Earth were to double the distance from the Sun, by how much would the force decrease?
- If the Earth were to triple the distance from the Sun, by how much would the force decrease?
2. Describe two ways in which gravitational forces are like electromagnetic forces.
3. Describe two ways gravitational forces and electromagnetic forces are different.
4. An astronaut having a mass of 65 kg is standing on the surface of the moon. The mass of the moon is 7.36 x 1022 kg and the radius is 1.74 x 106 m. What is the weight of the astronaut here on the moon.
5. You are standing on a very tall platform; so tall that you’ve just made it into space. You measure you weight and determine it to be 141 N.
a. If the platform shrinks, and you get closer to earth, what will happen to your weight?
b. When you’ve cut the distance from the earth in half, what is your weight?
6. If the Sun were to turn into a black hole (shrink down to a very small size) with the same mass as it has nowwould the intensity of the Sun’s gravity change at the orbit of the Earth? Explain your answer.
7. You are standing on the surface of the Earth. All of a sudden, the massof the Earth doubles and your mass doubles. The size of the Earth isunchanged. How far from the center of the Earth do you have to moveso that your weight will be the same as what it was before the masses changed?
8. You and your friend are standing 2 meters apart. If your mass is 56 kg and your friend’s mass is 94 kg, what is the magnitude of the gravitational force between you? (write your answer in scientific notation)
9. When you walk across a carpet, you scuff electrons from your shoes onto the carpet.
a. Are your shoes positively or negatively charged?
b. Is the carpet positively or negatively charged?
10. Consider an apple at the top of a tree that is pulled by Earth’s gravity with a force of 1 N. If the tree were twice as tall, would the force of gravity be only ¼ as strong? Explain your answer.
11. Voltage in electric circuits is similar to pressure in fluid circuits. A pressure difference between two points in a complete fluid circuit will make fluids move. A voltage difference between two points in a complete electric circuit will make ______move.
12. If an object with a charge of 2X10-8 C were placed 0.02 m from an object with a charge of 2.3X10-2, what would the magnitude of the force be?
13. When electrical current moves in only one direction through an electrical circuit it is called ______current.
14. Two objects 2m apart have charges of –2.08X 10-16C and –5.12X10-15C.Will these objects attract or repel?
15. The variable that represents charge is ______and the unit for charge is _____.