Chapter 3 - Motion in Two Dimensions - Learning Path Questions and Exercises - Exercises - Page 99: 48

$\theta=17.65^{\circ}$

Let angle be $\theta$. Horizontal velocity $=770cos\theta \,m/s$ So, $t=\frac{35000m}{770cos\theta} s=\frac{45.45}{cos\theta}s$ $S=ut+\frac{1}{2}at^{2}$ $0=770sin\theta\times t -4.9t^{2}$ $770sin\theta=4.9\times\frac{45.45}{cos\theta}$ $sin2\theta=0.578$ $2\theta=35.3^{\circ}$ $\theta=17.65^{\circ}$