Projectiles A and B are thrown at angles of $$45^{\circ}$$ and $$60^{\circ}$$ with vertical respectively from top of a $$400 \mathrm{~m}$$ high tower. If their ranges and times of flight are same, the ratio of their speeds of projection $$v_A: v_B$$ is :

[Take $$g=10 \mathrm{~ms}^{-2}$$]

Position of an ant ($$\mathrm{S}$$ in metres) moving in $$\mathrm{Y}$$-$$\mathrm{Z}$$ plane is given by $$S=2 t^2 \hat{j}+5 \hat{k}$$ (where $$t$$ is in second). The magnitude and direction of velocity of the ant at $$\mathrm{t}=1 \mathrm{~s}$$ will be :

A projectile is projected at $$30^{\circ}$$ from horizontal with initial velocity $$40 \mathrm{~ms}^{-1}$$. The velocity of the projectile at $$\mathrm{t}=2 \mathrm{~s}$$ from the start will be : (Given $$g=10 \mathrm{~m} / \mathrm{s}^{2}$$ )

Two projectiles are projected at $$30^{\circ}$$ and $$60^{\circ}$$ with the horizontal with the same speed. The ratio of the maximum height attained by the two projectiles respectively is: