A bullet is fired vertically upwards with velocity v from the surface of a spherical planet. Whenit reaches its maximum height, its acceleration due to the planet’s gravity is $$\frac{1}{4^{th}}$$ of its value at the surface of the planet. If the escape velocity from the planet is $$v_{esc} = v\sqrt{N}$$, then the value of N is (ignore energy loss due to atmosphere)