Posted by Sarah on Thursday, March 8, 2012 at 9:13pm.
In the figure, two balls are located in deep space. The black ball has mass 56kg and the red ball has mass 17kg. The distance between the two balls is r=24cm.
(a) Find the magnitude of the acceleration of the red ball.
m/s2
(b) If r is 5 times larger, with what factor will the acceleration of the red ball change?
(c) If the mass of the black ball is 45 times larger, with what factor will the acceleration of the red ball change?
(d) If the mass of the red ball is 50 times larger, with what factor will the acceleration of the red ball change?

Physics  drwls, Thursday, March 8, 2012 at 9:54pm
If you had shown some work, I would be willing to help. You are apparently using the service to harvest answers. Good luck.

Physics  Sarah, Thursday, March 8, 2012 at 10:45pm
i'm not sure how to begin the problem at all. Or else I would have shown some work. thanks though

Physics  drwls, Friday, March 9, 2012 at 12:51am
(a) Get the force acting on each ball from Newton's universal law of gravity. That's whereto begin.
Force = G*M1*M2/r^2 (same for both balls)
G = universal constant
M1 = black ball mass
M2 = red ball mass
The acceleration of the red ball will be that force divided by the mass of the red ball.
(b) What happens when you multiply r by 5?
(c) 45
(d) a = Force/M2 is unchanged 
Physics  Sarah, Friday, March 9, 2012 at 1:50pm
thank you for your help! I really appreciate it.