A shown in Figure, a person A is standing at he centre of a rotating platform facing person B who is riding a bicycle, heading East. The relevant speeds and distances are shown in given figure person, a bicycle, heading East. At the instant under consideration, what is the apparent velocity of B as seen by A?

If $$'P'$$ is the gauge pressure within a spherical droplet, then gauge pressure within a bubble of the same fluid and of same size will be:

Kinematic viscosity of air at $${20^0}C$$ is given to be $$1.6 \times {10^{ - 5}}\,\,\,{m^2}s.$$ Its kinematic viscosity at $${70^0}C$$ will be varying approximately :

Water flows through a vertical contraction from a pipe of diameter $$d$$ to another of diameter $$d/2$$ (see Figure). The flow velocity at the inlet to the contraction is $$2m/s$$ and pressure $$200$$ $$kN/{m^2}.$$ If the height of the contraction measures $$2m$$, then pressure at the exit of the contraction will be very nearly