- #1

mohamed_a

- 36

- 6

imagine an elastic collision occurred between sphere of mass (M) attached to a string forming a circle of radius (R) and moving with velocity (V) and another stationary sphere having the same variables but with lower case.

let M=m

mrv = mRV

rv = RV

if R = 2r

v = 2V

how is that possible although using kinetic energy gives the following:

0.5mv^2 = 0.5MV^2

v = V

Radius should be omitted from first equation since the speed is the same in two spheres and this doesn't mean that they will REVOLVE with same radial velocity since W = V/R so the sphere attached to ahorter rope will revolve faster.