Maximum Range in General

Q. Which of these is the formula for fining maximum horizontal range of a projectile given its initial velocity and angle of projection?

1. $\frac{u^{2}sin2\theta }{g}$
2. $\frac{u^{2}sin2\theta }{2g}$
3. $\frac{2u^{2}sin2\theta }{g}$
4. $\frac{2usin2\theta }{g}$

Q.

The maximum range of a gun on horizontal terrain is 16 km. If g = 10m/$s^2$. What must be the muzzle velocity of the shell

1. 200 m/s

2. 400 m/s

3. 100 m/s

4. 50 m/s