# Circular Motion of a plane

1. Oct 18, 2006

### ysk1

I'm stuck on the questions below.
Please tell me how to solve them.
Thank you.

1. How fast must a plane fly along the earth's equator so that the sun stands still relative to the passengers? In which direction must the plane fly, east to west or west to east? Give your answer in km/hr. The radius of the earth is 6400 km.

2. Satellites are placed in a circular orbit where they stay directly over a fixed point on the equator as the earth rotates. The altitude of a satellite's orbit is 3.58 x 10^7 m.
a. What is the priod of a satellite in a geosynchronous orbit?
b. Find the value of g at this altitude.

3. A 2.0 kg ball swings in a vertical circle on the end of an 80-cm-long string. The tension in the string is 20 N when its angle from the highest point on the circle is theta = 30 degrees.
a. What is the ball's speed when theta = 30 degrees?
b. What are the magnitude and direction of the ball's acceleration when theta = 30 degrees?

2. Oct 18, 2006

### OlderDan

Please show us what you have tried to solve these problems

3. Oct 18, 2006

### civil_dude

At least try to solve a portion of the problem. This could be .... I know the earth spins at 1 revolution per day = 2 pi radians per day, and I know that the earth is 3950 miles in radius. What do I do now?

At least put forth some question YOU have, not just post a question.