(b) $Maximum\ height\ H = \frac{v^{2}\cos^{2}\beta}{2g}$ $or\ \ vcos\beta = \sqrt{2gH}$ $t = \frac{vcos\beta}{g} = \frac{\sqrt{2gH}}{g}$ $t = \sqrt{\frac{2H}{g}}$
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.