The speed of a projectile at its maximum height is half of its initial speed. The angle of projection is

A particle moves in x-y plane according to rule x = asin$$\omega $$t and y = acos$$\omega $$t. The particle follows

Six vectors, $$\overrightarrow a $$ through $$\overrightarrow f $$ have the magnitudes and directions indicated in the figure. Which of the following statements is true ?

A particle has initial velocity $$\left( {3\widehat i + 4\widehat j} \right)$$ and has acceleration $$\left( {0.4\widehat j + 0.3\widehat j} \right).$$ Its speed after 10 s is