An object is projected with a velocity of 50ms-1 from ground level at an angle θ to the vertical. If the total time of flight of the projectile is 5s, what is the value of θ? (g = 10ms-2)
0°
30°
45°
60°
90°
Correct answer is D
Time of flight =\( \frac{2Usin\theta}{g}\)
T = 5, g = 10m/s2
\(5 = \frac {2\times 50sin\theta}{10}\)
\(sin\theta =\frac {50}{100}\)
\(\theta = 30\)
vertical angle = 90 - 30 = 60°