A ball of mass $m_1$ and another ball of mass $m_2$ are dropped from equal height. If time taken by the balls are $t_1$ and $t_2$ respectively, then

The velocity of bullet is reduced from $200\; m / s$ to $100\; m / s$ while travelling through a wooden block of thickness of $10 \;cm$ . The retardation assuming to be uniform, will be ...........$\times {10^4}\, m/s^2$

A bus is moving with a velocity $10 \,m/s$ on a straight road. A scooterist wishes to overtake the bus in $100\, s$. If the bus is at a distance of $1 \,km$ from the scooterist, with what velocity should the scooterist chase the bus......... $m/s$

Two buses $P$ and $Q$ start from a point at the same time and move in a straight line and their positions are represented by $X _{ P }( t )=\alpha t +\beta t ^{2}$ and $X _{ Q }( t )= ft - t ^{2}$. At what time, both the buses have same velocity $?$

A particle is projected vertically upwards from a point $A$ on the ground. It takes $t_1$ time to reach a point $B$ but it still continues to move up. If it takes further $t_2$ time to reach the ground from point B then height of point $B$ from the ground is

A body travels for $15\, sec$ starting from rest with constant acceleration. If it travels distances ${S_1},\;{S_2}$ and ${S_3}$ in the first five seconds, second five seconds and next five seconds respectively the relation between ${S_1},\;{S_2}$ and ${S_3}$ is