A rocket is projected vertically upwards and its time velocity graph is shown in the figure-1.115. The maximum height attained by the rocket is :

Answer

0.75 hr, 1.5 hr after the moment of departure, No overtaking

Explanation

For A : `30t_(1)=S//2=60 (2-t_(1))rArr t_(1)=4//3` hr (Here S is the total distance and `t_(1)` is time up to which A's speed is `30 km//hr`)
For B : `1/2xxaxx2^(2)=(30xx4/3)xx2=S`
`rArr a=40 km//hr^(2)`
(i) (a) `v_(B)=40t=30rArrt=0.75` hr
(b) `v_(B)=40t=60rArr t=1.5` hr
(ii) there is no overtaking.