A projectile is fired from level ground at an angle $\theta $ above the horizontal. The elevation angle $\phi $ of the highest point as seen from the launch point is related to $\theta $ by the relation
$\tan \,\phi = \frac{1}{4}\,\tan \,\theta $
$\tan \,\phi = \tan \,\theta $
$\tan \,\phi = \frac{1}{2}\,\tan \,\theta $
$\tan \,\phi = 2\,\tan \,\theta $
A projectile is projected with velocity of $25\, m / s$ at an angle $\theta$ with the horizontal. After t seconds its inclination with horizontal becomes zero. If $R$ represents horizontal range of the projectile, the value of $\theta$ will be : [use $g =10 m / s ^{2}$ ]
If the time of flight of a bullet over a horizontal range $R$ is $T$, then the angle of projection with horizontal is ......
Two bodies are projected with the same velocity. If one is projected at an angle of ${30^o}$ and the other at an angle of ${60^o}$ to the horizontal, the ratio of the maximum heights reached is
The maximum height attained by a projectile is increased by $10\,\%$ by increasing its speed of projection, without changing the angle of projection. The percentage increases in the horizontal range will be $...........\,\%$
A boy travelling in an open car moving on a levelled road with constant speed tosses a ball vertically up in the air and catches it back. Sketch the motion of the ball as observed by a boy standing on the footpath. Give explanation to support your diagram.