A $40\ g$ ball dropped from a certain height bounces back from the horizontal ground without losing mechanical energy. If its speed is $10\ m/s$ just before making contact with the ground, and the average value of the force of the ground on the ball is equal to $16\ N$ while ball and wall are in contact, how long were they in contact .......... $m/s$ 

The momentum is most closely related to

A body is accelerated by applying a force of $30\,N$. The change in the momentum of the body after $2\,sec$ is ............ $kg-m/s$ 

When the speed of a moving body is doubled

A body of mass $10 kg$ is projected at an angle of $45^{\circ}$ with the horizontal. The trajectory of the body is observed to pass through a point $(20,10)$. If $T$ is the time of flight, then its momentum vector, at time $t =\frac{ T }{\sqrt{2}}$, is.

$\left[\right.$ Take $\left.g=10 m / s ^{2}\right]$

A ball is thrown up at an angle with the horizontal. Then, the total change of momentum by the instant it returns to the ground is