A book is lying on the table. What is the angle between the action of the book on the table and the reaction of the table on the book?
$0\ rad$
$\frac{\pi }{4}\ rad$
$\frac{\pi }{2}\ rad$
$\pi \ rad$
Which of the following groups of forces could be in equibrium
At the instant $t = 0$ a force $F = kt$ ( $k$ is a constant) acts on a small body of mass $m$ resting on a smooth horizontal surface. The time, when body leaves the surface is
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
In Newtonian mechanics which parameter apply external force ?
An $80\, kg$ person is parachuting and is experiencing a downward acceleration of $2.8\, m/s^2$. The mass of the parachute is $5\, kg$. The upward force on the open parachute is ........... $N$ (Take $g = 9.8\, m/s^2$)