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Space Probe with Constant Acceleration

In the animation shown (position is given in meters and time is given in seconds), a space probe has engines that can fire on all four sides.  Two of the engines engage at t = 2 s.  Restart.  The acceleration is constant and zero before the engines engage, and it is constant (but not equal to zero) after the engines engage. 

1. What is the direction of the acceleration after the engines engage? 
2. Describe the shape of the path of the space probe. What can you say about the shape of the path of any object that has a constant acceleration, regardless of its initial velocity and its acceleration? 
3. Now click here to view the velocity and acceleration vectors.  Do they match what you predicted?
4. Suppose that the initial velocity (velocity at t=2 s) of the probe was perpendicular to the acceleration of the probe after the engine start firing. What would its path look like? Click here to see the motion.
Note that it is not circular motion, like one might guess. Circular motion requires a uniform radial acceleration.
5. Based on your investigations, describe the path of an object in three possible cases: (1) the initial velocity is not zero, but the acceleration is zero; (2) The angle between the initial velocity and acceleration is not equal to 0 or 180°; (3) The initial velocity is in the same direction or in the opposite direction as the acceleration.

Physlet authored by Aaron Titus with support by the National Science Foundation under Grant No. DUE-9952323 and placed in the public domain. It can also be found in the book Physlet Physics by Wolgang Christian and Mario Belloni.

are scriptable Java Applets written by Wolfgang Christian of Davison College.