For three vectors $u, v, w$,which of the following expressions is not equal to the other three?

The equation of the parabola with focus $(0, 0)$ and directrix $x + y = 4$ is

The tyre of a motor car contains air at $15^{\circ} C$. If the temperature increases to $35^{\circ} C$,the approximate percentage increase in pressure is (ignore the expansion of the tyre).

$X$ and $Y$ are two metals. When burnt in air,$X$ forms only oxide while $Y$ forms oxide and nitride. The metals $X$ and $Y$ may be

Two rods of different materials having coefficients of linear expansion $\alpha_1$ and $\alpha_2$ and Young's moduli $Y_1$ and $Y_2$ respectively are fixed between two rigid massive walls. The rods are heated such that they undergo the same increase in temperature. There is no bending of rods. If $\alpha_1 : \alpha_2 = 2 : 3$,the thermal stress developed in the two rods is equal provided $Y_1 : Y_2$ is equal to:

What is the approximate weight of the flower of $Rafflesia$ $arnoldii$ (in $kg$)?