Name:Class Period: Date:

Modeling Gravity Lab

Part 1: Go to And select RUN

Qualitative Observations

Adjust the masses and distances to see what happens to the force of gravity between the two masses.

  1. How does the separation of the masses affect the force between them?
  1. What happens to the force between the objects when mass 1 is tripled?
  1. What happens to the force between the objects if you Cut Mass 2 in half?
  1. In any of the situations did the forces ever differ in magnitude?What model(s) apply?
  1. In any of the situations did the forces ever not point in opposing directions?What model(s) apply?

Quantitative

It is now time to build a model.

  1. What THREE things can we change/vary?
  1. Select an independent and dependent variable and constant
  1. DV ______
  1. IV ______
  1. C ______
  1. Collect 10 data pointsand graph using your Graphing calculator or online Graphing ( is an option) and insert a copy of your graph below.
  1. Select a new independent and dependent variable and constant
  1. DV ______
  1. IV ______
  1. C ______
  1. Collect 10 data pointsand graph. Insert a copy of your graph below.

Part 1: Questions

  1. How did varying the second mass affect your results?
  1. What is the relationship between Mass and force?
  1. What is the relationship between distance and the force of gravity? (This one is a little tricky.)
  1. Write out the proportions between Mass 1 (m1), Mass 2 (m2) distance (r) to the Force of gravity (FG).

Check with your instructor to make sure your proportionality is correct.

  1. Does your lab data for m1, m2, and r does equal Fg? Also work out your units, do they equal a unit of force?
  1. Make a graph of Force vs. your proportionality in Excel. (Put the Force on the vertical axis)
  1. Determine the gravitational constant (G) that will satisfy your units

G=______

  1. Write your full formula and check with your instructor.

Part 2: Go to select RUN

Run several simulations, changing parameters as you go. Answer the following questions:

  1. What direction is the gravitational force of the orbiting object?
  1. What direction is the velocity of the orbiting object?
  1. If you turn gravity off, what happens? Why does this happen?
  1. If you increase the mass of the Sun, what happens to the Earth?
  1. If you decrease the mass of the Sun, what happens to the Earth?
  1. Click on the Earth/satellite button. Increase the speed of the satellite. What happens? Explain.
  1. Decrease the speed of the satellite. What happens? Explain.
  1. Move the satellite. Describe what happens. Can you create a stable orbit further from the Earth? How did you do it?
  1. Change the mass of the satellite only. Will this change the orbit of the satellite? Why or Why not? Explain what happens.
  1. The mass of the moon is 7.35x1022kg and the mass of the earth is 5.97x1024kg. The moon’s orbit distance is 3.84x108m. What is the gravitational force on the moon by the earth? What is the gravitational force of the earth on the moon?
  1. What is the centripetal acceleration of the moon around the earth, realizing that the gravitational force is the centripetal force?
  1. What is the speed of the moon as it travels around the Earth?