A particle is thrown with a speed $u$ at an angle $\theta$ with the horizontal. When the particle makes an angle $\phi$ with the horizontal, its speed changes to $v$, where
$v=u \cos \theta$
$v=u \cos \theta \cos \phi$
$v=u \cos \theta \sec \phi$
$v=u \sec \theta \cos \phi$
Derive the formula for Range of a projectile $(R)$. Derive the formula for maximum projectile.
For a given velocity, a projectile has the same range $R$ for two angles of projection if $t_1$ and $t_2$ are the times of flight in the two cases then
Two stones having different masses $m_1$ and $m_2$ are projected at an angle $\alpha$ and $\left(90^{\circ}-\alpha\right)$ with same speed from same point. The ratio of their maximum heights is
Two bodies are thrown up at angles of $45^o$ and $60^o$, respectively, with the horizontal. If both bodies attain same vertical height, then the ratio of velocities with which these are thrown is
Three identical balls are projected with the same speed at angle $30^o, 45^o$ and $60^o$. Their ranges are $R_1 R_2$ and $R_3$ respectively. Then