# Asteroids and their total energy

1. Jun 19, 2013

http://s9.postimg.org/vejo37agv/physics.jpg [Broken] for picture

Asteroids X, Y, Z have equal mass (6kg each). They orbit around a planet with M=6×1024kg. The orbits are in the plane of the paper and are drawn to scale.

TE, KE and PE represent Total, Kinetic and Potential energies.
Select G-Greater than, L-Less than, or E-Equal to. (If the first is G and the rest L, enter GLLLLLL).

A) The KE of Y at 7 is .... its value at 5.
B) The speed of X at 6 is .... it is at 5.
C) The PE of X at 5 is .... the PE of Y at 5.
D) The PE of X at 5 is .... the PE of Y at 7.
E) The TE of Z is .... the TE of X.
F) The TE of Y is .... the TE of Z.
G) The PE of X at 5 is .... its value at 3.

Hello, guys I've attempted this many times. My most certain answer is ELEELGl. I was wondering if anyone could help me with this. I am pressure sure A B C D G are correct. But i am not sure about E and F. I've tried ELEEGLl and ELEEEEl also. Those don't work either.

The unit is on conservation of energy.

Last edited by a moderator: May 6, 2017
2. Jun 19, 2013

### Andrew Mason

How is the total energy related to: 1. the length of the semi-major axis of the elliptical orbit or 2. the radius of a circular orbit? Is the semi-major axis of Z greater or less than the radius of Y? You may have to measure this to find out.

AM