Question:
A player kicks a football with an initial speed of $25 \mathrm{~ms}^{-1}$ at an angle of $45^{\circ}$ from the ground. What are the maximum height and the time taken by the football to reach at the highest point during motion ? (Take $\mathrm{g}=10 \mathrm{~ms}^{-2}$ )
Correct Option: , 3
Solution:
$\mathrm{H}=\frac{\mathrm{U}^{2} \sin ^{2} \theta}{2 \mathrm{~g}}$
$=\frac{(25)^{2} \cdot(\sin 45)^{2}}{2 \times 10}$
$=15.625 \mathrm{~m}$
$\mathrm{T}=\frac{\mathrm{U} \sin \theta}{\mathrm{g}}$
$=\frac{25 \times \sin 45^{\circ}}{10}$
$=2.5 \times 0.7$
$=1.77 \mathrm{~s}$