Performance Task – Planet Project

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Task: You and your lab partner are to design your own simple solar system with two planets orbiting a star similar to our sun. Each lab partner will be responsible for one planet within the system. You can be creative naming and designing your planet but you must stay within certain parameters so that calculations are reasonable (see control parameters below). These parameters will be provided based planetary objects within our own solar system. You can also assume your planet is spherical in shape and has a circular orbit around the sun. Once you have created your planet you will be required to calculate a number of properties and phenomena associated with your planet based on the parameters you choose.

Data Table
name
ms / 1.99 x 1030 kg
mp
ds
rp
m
d
Fw

Step I: Choose your parameters for your solar system and place in the data table

Choose the name of your planet

Sun (ms) - The sun will be the same as our sun and is provided for you

Choose your planets mass (mp) - between 5.00 x 1020kg and 5.00 x 1026kg

Choose your planet’s distance from sun (ds)- between 5.00 x 1010m and

5.00 x 1012 m. Note: Assume this distance is from the centers of both ms and mp.

Choose your planets radius (rp) - between 5.00 x 105m and 5.00 x 107m

Write down your partner’s planet mass (m)

Write down your partner’s planet distance from the sun (d)

Record your weight in Newtons (Fw)- Your weight in pounds multiplied by 4.4 5N/lb

Step: II: Using the values from your data table calculate the surface gravity or acceleration due to gravity (gp) on your planet. First write down the correct relationship needed that was derived in class.

Now plug in the data values and show your work below. Write your final answer in the Results Table.

Step III: Convert your weight into kilograms by dividing by 9.8 m/s2 then using your planet’s acceleration due to gravity (gp) to calculate and record your weight (Fw) on the surface of your planet in your Results Table. Show your work below. Remember Fw = mgp !

Results Table (Units)
Acceleration due to gravity on your planet (gp) / m/s2
Your Weight on your planet (Fw) / N
Orbital Velocity
For your planet (Vorb) / m/s
Length of a year on your planet in Earth days (T) / days
Force of gravity between you and your partner’s planet (Fg) / N
Density of your planet (D) / kg/m3

Step IV Using the data from table I calculate the velocity of a satellite 100,000 km above your planet (Vorb). Assume you are above any possible atmosphere. First write down the correct relationship needed that was derived in class.

Now plug in the data values and show your work below. Include a diagram similar to the one used in example III form your class notes. Write your final answer in the Results Table.

Step V: Using the data from your data table calculate the time in seconds (T) it would take for your planet to orbit the sun. First write down the correct relation needed that was derived in class.

Now plug in the data values and show your work below. Convert your answer into days by dividing by 86,400 sec/day and record your final answer in days in the Results Table.

Step VI: Draw a picture of your planet and your partner’s planet on opposite sides of the sun. Label the planets and sun and indicate the distance from the sun for each planet with an arrow as shown in class. Have fun with your diagram and embellish it in creative ways if you wish.

Step VII: Calculate the pull of gravity between your planet and you partner’s planet (Fg) when they are on opposites sides of the sun as shown in your diagram above. Show your work below and record your final answer in your Results Table.

Step VIII: Calculate the density of your planet by taking mass and dividing by its volume (D = m/V) . The volume can be found using the formula for a sphere V =4 3πr3 where r = rp the radius of your planet. Show your work below and record your density in your Results Table.

Question 1) What would happen to the surface gravity (g) of your planet if you were to shrink its radius in half without changing its mass?

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Question 2) What do you think happens to the surface gravity of a planet as you move inside the planet closer and closer to the center of the planet? Think about how gravity works and the fact that every bit of mass is attracted to every other bit of mass.

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Question 3) How does the mass of a satellite affect its velocity when orbiting your planet?

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Writing Prompt: Planets in our solar system are of two basic types small, solid, and rocky like the Earth or large and gaseous like Saturn or Jupiter. Research the density of other planets and comment on what type of planet you think you have created. Your planet may even fall outside the density range of “ordinary” planets. Please be sure to justify your answer.

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