A massive disc of radius R is moved with a constant velocity m on a frictionless table. Another small disc collides with it elastically with a speed of\[{{v}_{0}}= 0.3 m/s\], the velocities of the discs being parallel. The distance (/shown in the figure is equal to R/2, friction between the discs is negligible. For which u (in m/s) will the small disc move perpendicularly to its original motion after the collision?

A massive disc of radius R is moved with a constant velocity m on a fr

1.	A massive disc of radius R is moved with a constant velocity m on a frictionless table. Another small disc collides with it elastically with a speed of\[{{v}_{0}}= 0.3 m/s\], the velocities of the discs being parallel. The distance (/shown in the figure is equal to R/2, friction between the discs is negligible. For which u (in m/s) will the small disc move perpendicularly to its original motion after the collision?
A.	0.1
B.	0.5
C.	1
D.	0.01
Answer» B. 0.5