A jet of liquid of cross-sectional area $'a'$ strikes a wall making angle $\theta $ with wall. The water strikes with the wall with velocity $v$ and rebounds elastically. If density of liquid be $\rho $, the normal force on the wall is
$2a{v^2}\rho \,\sin \,\theta $
$2a{v^2}\rho \,\cos \,\theta $
$2av\rho \,\sin \,\theta $
$2av\rho \,\cos \,\theta $
Ten one-rupeed coins are put on top of each other on a table. Each coin has mass $m$. The reaction of the $6^{th}$ coin (counted from the bottom) on the $7^{th}$ coins is .......... $mg$
A body of mass $m$ hangs at one end of a string of length $l$, the other end of which is fixed. It is given a horizontal velocity so that the string would just reach where it makes an angle of $60^o$ with the vertical. The tension in the string at mean position is
There are four forces acting at a point $P$ produced by strings as shown in figure, point $P$ is at rest. The forces $F_1$ and $F_2$ are respectively