Asatellite in circular orbit around the earth moves at constant speed. this orbit is maintained by the force of gravity between the earth and the satellite, yet no work is done on the satellite. no work is done because there is no gravity in space. no work is done if objects move in a circle. no work is done if the direction of motion is perpendicular to the force. no work is done if there is no contact between objects.

No work is done if the direction of motion is perpendicular to the force.

Explanation:

The speed of a satellite in a circular orbit changes in direction but not in magnitude, that is why it remains constant, but its velocity is changing along the time. Now, in this case, the direction of the motion is perpendicular to the acting force, which is the centripetal force, and knowing that the work is proportional to the scalar product of force and displacement, no work is done on the satellite.

I hope it helps you!

molecules are free to separate from each other and will take on the shape of the container. molecules move completely at random and high speeds. they vibrate in a fixed position and do not move around much. molecules expand to the edge of their container.

conservation of mass

mass before something happens = mass afterwards