A ball is thrown vertically upwards and rises to a height of 126.5 m. Calculate the

(i) velocity by which the ball was thrown upwards and

(ii) the time taken by the ball to reach the highest point. (Given is g = 9.8 ms–²)

At Least 100 to 150 words

Asked by Aryungupta.espn | 30th Dec, 2019, 03:34: PM

Expert Answer:

h = 126.5 m 
 
i) 
v2 - u2 = 2as 
As the ball is moving against the gravity when thrown upward, 
 
v2 - u2 = 2gh
Thus, 
0 = u2 + 2 (-9.8) × (126.5) ... (negative sign of 'g' indicate that the object is moving against the gravity)
u2 =  2479.5
Thus, 
u = 49.79≈ 50 m/s
 
Thus, the velocity by which the ball must be thrown upward is 49.79 m/s
 
ii) time taken by the ball to reach the highest point is given as, 
v = u + gt
Thus, 
0 = 49.79 + (-9.8) x t 
Thus, 
t = 5.08 s

Answered by Shiwani Sawant | 30th Dec, 2019, 06:39: PM