A dynamometer $D$ is attached to two blocks of masses $6 \,kg$ and $4 \,kg$ as shown in the figure. The reading of the dynamometer is ............ $N$

If net force on a system is zero then

One end of a string of length $l$ is connected to a particle of mass $m$ and the other to a small peg on a smooth horizontal table. If the particle moves in a circle with speed $v$ the net force on the particle (directed towards the centre) is :

$(i) \;T,$ $(ii)\; T-\frac{m v^{2}}{l},$ $(iii)\;T+\frac{m v^{2}}{l},$ $(iv) \;0$

$T$ is the tension in the string. [Choose the correct alternative].

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 $g = 9.8\, m/s^2$)

A weight can be hung in any of following four ways by using same string. In which case is  the string more likely to break is :-

In order to test the strength of a rope, one end is tied to a large tree and the other end is  hitched to a team of $2$ horses. The horse pull as hard as they can, but cannot break the  rope. If the rope is untied from the tree and attached to another team of $2$ horses  with equal strength, and the two teams pull in opposite directions, the tension in the rope  will