Galileo writes that for angles of projection of a projectile at angles $(45^\circ + \theta)$ and $(45^\circ - \theta)$,the horizontal ranges described by the projectile are in the ratio of (if $\theta \le 45^\circ$):

$A$ projectile can have the same range for two angles of projection. If $h_1$ and $h_2$ are the maximum heights when the range in the two cases is $R$,then the relation between $R$,$h_1$,and $h_2$ is:

$A$ missile is fired for maximum range at your town from a place $100 \, km$ away from you. If the missile is first detected at its half-way point,how much warning time will you have? (Take $g = 10 \, m/s^2$). What was the speed of the missile when it was detected?

$A$ shell is fired at an angle of $30^{\circ}$ to the horizontal with a velocity of $196 \,m/s$. What is the time of flight (in $\,s$)? (Take $g = 9.8 \,m/s^2$)

$A$ stone is projected with kinetic energy $E$,making an angle $\theta$ with the horizontal. When it reaches its highest point,its kinetic energy is

$A$ fighter jet is flying horizontally at a certain altitude with a speed of $200 \; m/s$. When it passes directly overhead an anti-aircraft gun,a bullet is fired from the gun at an angle $\theta$ with the horizontal to hit the jet. If the bullet speed is $400 \; m/s$,the value of $\theta$ will be $\dots \; ^\circ$.