In the given diagram, the tension in the string $C$ is:- 

A sphere of mass m is kept in equilibrium with the help of several springs as shown in the figure. Measurements show that one of the springs applies a force $\overrightarrow{\mathrm{F}}$. on the sphere. With what acceleration the sphere will move immediately after this particular spring is cut?

In the set-up shown, a 200 N block is supported in equilibrium with the help of strings and a spring, all knotted at point O. Extension in the spring is 4 cm. Force constant of the spring is closest to [g = 10 m/s²]
                                     

A lift of mass $100 \mathrm{kg}$ starts moving from rest in the upward direction. Figure shows the variation of speed of the lift. If T₁, T₂ and T₃ stand for tension in the rope from zero to two seconds, two to six seconds, six to seven seconds respectively, then :-
                                  

All surfaces are assumed to be frictionless. Calculate the horizontal force F that must be applied so that m₁ and m₂ do not move relative to m₃ is :-
                                      

Two masses of 1 kg and 2 kg are attached to the ends of a massless string passing over a pulley of negligible weight. The pulley itself is attached to a light spring balance as shown in figure. The masses start moving; during this interval the reading of spring balance will be:-