# Circular Motion - Spacecraft in Orbit

• Becca93

#### Becca93

Homework Statement

A spacecraft moves in a circular orbit with a speed of 7.60E+0 km/s with a period of 95.1 min. What is the radius of the spacecraft 's orbit?
My answer, which is correct, is 6.90×106 m

What is the radial acceleration of the satellite?
8.37 m/s^2 was my answer, and it is correct.

My issue begins right here:

In order to begin its re-entry, the spacecraft engines are fired to provide an acceleration of 6.70 m/s2 in a direction opposite to its velocity. What is the magnitude of the spacecraft 's total acceleration just after the engines begin to fire.

The attempt at a solution

The only thing I really grasp from this last question is that it starts going in the opposite direction, meaning you have to overcome the velocity it is originally going into go the other way. Otherwise, I don't know where to start.

Last edited:
When the engine starts firing you have two accelerations acting on the craft. The radial from it's orbit and the tangential from the engines. I think the question wants you to add them as vectors and get the total magnitude.

Thank you! I managed to get the answer. I appreciate the guidance.