Figure shows the velocity-time graph for two masses `R` and `S` that collided elastically. Which of the following statements is true?

i. `R` and `S` moved in the same direction after the collision.
ii. The velocities of `R` and `S` were equal at the mid time of the collision.
iii. The mass of `R` was greater than mass of `S`.
Which of the following is true?

Options

A. ionly
B. ii only
C. i and ii only
D. i,ii, and iii

Answer

D

Explanation

Since both have positive final velocities hene, both moved in the same direction after collision.
ii At `t=2s`, both had equal velocities.
iii By conservation of linear momentum,
`m_(1)(0.8)=m_(1)(0.2)+m_(2)(1)=m_(1)/m_(2)=5/3impliesm_(1)gtm_(2)`