If the pair of lines

$$a{x^2} + 2hxy + b{y^2} + 2gx + 2fy + c = 0$$

intersect on the $$y$$-axis then :

Identify the pair whose dimensions are equal

A ball whose kinetic energy E, is projected at an angle of $$45^\circ $$ to the horizontal. The kinetic energy of the ball at the highest point of its height will be

From a building two balls A and B are thrown such that A is thrown upwards and B downwards ( both vertically with the same speed ). If v_A and v_B are their respective velocities on reaching the ground, then