From the top of a tower of height 50 m a ball is projected upwards with a speed of 30 m/s at an angle of 30° to the horizontal. Take g = 10 m/s². Find the time of flight (s).
Physics · Kinematics part-2 Projectile Motion · Projectile from height
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Question

From the top of a tower of height 50 m a ball is projected upwards with a speed of 30 m/s at an angle of 30° to the horizontal. Take g = 10 m/s². Find the time of flight (s).

G1 Physics · Accepted Answer

Vertical component of initial velocity is uᵧ = 30sin30° = 15 m/s. Taking the launch point as y = 0 and the ground 50 m below, -50 = 15t - 5t². Solving gives t² - 3t - 10 = 0, so the positive root is t = 5 s.