A projectile is thrown straight upward from the earth's surface with an initial speed $$v=\alpha v_e$$ where $$\alpha$$ is a constant and $$v_e$$ is the escape speed. The projectile travels upto a height 800 km from earth's surface, before it comes to rest. The value of the constant $$\alpha$$ is (radius of the earth $$=6400 \mathrm{~km}$$)
Same tension is applied to the following four wires made of same material. The elongation is longest in
A cone with half the density of water is floating in water as shown in figure. It is depressed down by a small distance $$\delta(\ll< H)$$ and released. The frequency of simple harmonic oscillations of the cone is
Statement (A) When the temperature increases the viscosity of gases increases and the viscosity of liquids decreases.
Statement (B) Water does not wet an oily glass because cohesive force of oil is less than that of water.
Statement (C) A liquid will wet a surface of a solid, if the angle of contact is greater than $$90^{\circ}$$.