Consider the structural system shown in the figure under the action of weight $$W.$$ All the joints are hinged. The properties of the members in terms of length $$(L),$$ area $$(A)$$ and the modulus of elasticity $$(E)$$ are also given in the figure. Let $$L,A$$ and $$E$$ be $$1$$ $$m,$$ $$0.05$$ $${m^2}$$ and $$30 \times {10^6}\,\,N/{m^2},\,\,$$ respectively, and $$W$$ be $$100$$ $$kN.$$

Which one of the following sets gives the correct values of the force, stress and change in length of the horizontal member $$QR$$?

The kinematic indeterminacy of the plane truss shown in the figure is

A motorist traveling at 100 km/h on a highway needs to take the next exit, which has a speed limit of 50 km/h. The section of the roadway before the ramp entry has a downgrade of 3% and coefficient of friction ( f ) is 0.35. In order to enter the ramp at the maximum allowable speed limit, the braking distance (expressed in m) from the exit ramp is ______