# Practice Page

## Not the quiz

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### 406-J: Finding the Mass of the Sun

• Topic Cluster: Dynamics
• Topic: Circular Motion
• Objective: Use the formulas for centripetal acceleration and gravitation to find the mass of the sun and earth.
• Content: Because the earth moves in a nearly perfect circle around the sun, the centripetal force acting on the earth is equal to the gravitational force pulling it towards the sun; this knowledge can be used to discover the mass of the sun.
• Level: 4

# Problem Set

Mass of the sun problem set.

Rules: you should complete the first problem with your notes, but without looking up any information online, except that provided.

##### Available information:
• Watch video, a classic moment in television history:
• A 5K (five kilometer) race is 3.1 miles long.

#### Problem 1:

With only this information, determine the mass of the sun.

#### Problem 2:

Look up 2 (and only two) pieces of information online. Using a similar method as you used in problem 1, determine ethe mass of the earth. You cannot look up any qualities of the earth, such as its mass (duh), its radius, its circumference, etc. You need to look up other information that is not about the earth per se, and from that, determine the mass of the earth.