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maximoanimo
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Homework Statement
Two spheres have equal radius R = 14m and mass m = 1420kg. Their centers are separated a distance 4R. The spheres are released from rest. What will be their speed when they collide? Answer in m/s.
Homework Equations
U(g) = -G*m1*m2/R
The Attempt at a Solution
We know from the conservation of energy that U(i) + K(i) = U(f) + K(f). Since the spheres are initially at rest, K(i) = 0. Initially, the two spheres are 4R apart. Upon collision, they must be 2R apart (the sum of their radii when they are touching). Knowing this information, we can plug in:
-Gm^2/4R = -Gm^2/2R + mv^2/2
-Gm^2/4R = -2Gm^2/4R + 2Rmv^2/4R
Gm^2 = 2Rmv^2
v^2 = Gm^2/2Rm = Gm/2R
Plugging in the values given, I found v = 5.8172e-5 m/s. However, it says this solution is incorrect. Can someone help me find the flaw in my solution?
Thanks so much,
Steven