The maximum height attained by projectile is increased by $10 \%$ by keeping the angle of projection constant. What is the percentage increase in the time of flight ?

The horizontal range of a projectile projected at an angle of $45^{\circ}$ with the horizontal is 50 m . The height of the projectile when its horizontal displacement is 20 m is

A body of mass 1.5 kg is moving towards south with a uniform velocity of $8 \mathrm{~ms}^{-1}$. A force of 6 N is applied to the body towards east. The displacement of the body 3 s after the application of the force is

If two stones are projected at angle $\theta$ and $\left(90^{\circ}-\theta\right)$ respectively with horizontal with a speed of $20 \mathrm{~ms}^{-1}$. If second stone rises 10 m higher than the first stone then, the angle of projection $\theta$ is (acceleration due to gravity $=10 \mathrm{~ms}^{-2}$ )