$A$ ball of mass $m$ is thrown vertically upwards. Assume the force of air resistance has magnitude proportional to the velocity,and direction opposite to the velocity. At the highest point,the ball's acceleration is

$A$ body is projected vertically upward from the surface of the Earth. If the upward direction is taken as positive,then the acceleration of the body during its upward and downward journey are respectively:

$A$ ball is dropped from a bridge that is $45 \ m$ above the water. It falls directly into a boat which is moving with constant velocity. The boat is $12 \ m$ away from the point of impact when the ball is dropped. The speed of the boat is (Take $g=10 \ m \ s^{-2}$) (in $m \ s^{-1}$)

$A$ body falling freely under gravity passes two points $30 \ m$ apart in $1 \ s$. From what point above the upper point did it begin to fall? (Take $g = 10 \ m \ s^{-2}$)

$A$ body falls from a height $h = 200\,m$ (at New Delhi). The ratio of distance travelled in each $2\,s$ interval during $t = 0$ to $t = 6\,s$ of the journey is

Two bodies of masses $m_1$ and $m_2$ are dropped from two different heights $h_1$ and $h_2$ respectively. The ratio of the times taken by the two masses to touch the ground is (neglect air resistance)