Question

A particle moves along positive X-axis with a velocity. (in a suitable unit) varying as (4 -3t- t²) where t is time in seconds Students draw following four conclusions.

(I) Initially the particle is at the origin.

(II) Initial speed of the particle is zero.

(Ill) The particle decelerates till t = 1 s.

(IV) The speed of the particle goes on increasing after t = 1 s.

Therefore, conclusions

(a) (i) & (ii) are sometimes correct, (iii) & (iv)are always correct,

(b) (i), (iii) & (iv) are always correct and (ii) is sometimes correct

(c) (i), (iii) & (iv) always correct, (ii) is never correct

(d) (i) is sometimes correct, (ii) is never correct, (iii) & (iv) are always correct

Answer 1

Correct option: (d) (i) is sometimes correct, (ii) is never correct, (iii) & (iv) are always correct

Explanation: 

That means particle deacelerates till t = 1 sec.

And speed of particle goes on increasing after t = 1 sec