A point moves with uniform acceleration and $v_1, v_2$ and $v_3$ denote the average velocities in the three successive intervals of time $t_1, t_2$ and $t_3$. Which of the following relations is correct?

A particle is thrown upwards from ground. It experiences a constant resistance force which can produce a retardation of $2 \mathrm{m} {\mathrm{s}}^{-2}$. The ratio of time of ascent to time of descent is ($g=10 \mathrm{m} {\mathrm{s}}^{-2}$)

A disc in which several grooves are cut along the chord drawn from  a point '$\mathrm{A}$', is arranged in a vertical plane, several particles starts slipping from '$\mathrm{A}$' along the grooves simultaneously. Assuming friction and resistance negligible,the time taken in reaching the edge of disc will be:

Two boats $A$ and $B$ are moving along perpendicular paths in a still lake at night. Boat $A$ move with a speed of $3{\mathrm{MS}}^{-1}$ and boat $B$ moves with a speed of $4{\mathrm{MS}}^{-1}$ in the direction such that they collide after sometime. At $t=0,$ the boats are $300\mathrm{m}$ apart. the ratio of distance travelled by boat $A$ to the distance travelled by boat $B$ at the instant of collision is:

A trolley is moving horizontally with a constant velocity of  $v m{s}^{-1}$ $\mathrm{w}.\mathrm{r}.\mathrm{t}.$ earth. $\mathrm{A}$ man starts running from one end of the trolley with a velocity of $1.5{\mathrm{vms}}^{-1}\mathrm{w}.\mathrm{r}.\mathrm{t}.$ to trolley. after reaching the opposite end, the man return back and continues running with a velocity $1.5{\mathrm{vms}}^{-1}\mathrm{w}.\mathrm{r}.\mathrm{t}.$ the trolley in the backward direction. If the length of the trolley is $L$ then the displacement of the man with  respect to earth during the process will be: