Question

From the top of a tower of height 40 m a ball is projected upwards with a speed of 20 m/s at an angle of elevation of 30 degree . Then the ratio of the total time taken by the ball to hit the ground to its time of flight (time taken to come back to the same elevation) is (take g = 10 ms2) (a) 2 : 1 (b) 3 : 1 (c) 3 : 2 (d) 4 : 1

Answer 1

ANSWER

Time of flight,

T=g2vsinθ​=102×20×sin30°​=2sec

Total time taken by the ball to hit the ground is

t=velocitydistance​=20sin30°40​=20×21​40​=4sec

So, the ratio is 4:2=2:1