Work Energy And Power Question 298
Question: 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?
Options:
A) 0.1
B) 0.5
C) 1.0
D) 0.01
Show Answer
Answer:
Correct Answer: A
Solution:
[a] $ {V _{0y}}=V_0 sin \theta $ , this component does not change $ v _{0x} = v_0 cos\theta and u cos \theta $
For elastic collision relative velocity before collision is equal to relative velocity after collision along $ x-axis $
$ v_0\cos \theta -ucos\theta =ucos\theta +v _{x} $
$ Ifv _{x} cos\theta =v _{0y}Sin\theta $ By solving $ m=0.1 $
