Question

A ball is trown vertically upwards with an initial velocity of 49m/sec.calculate (1)maximum height attained. (2)the time taken by it reaches the ground again.

Answer 1

hello ...
your answer ....

(1)initial velocity of ball,u = 49 m/s
final velocity of ball , v = 0 m/s

gravity acting on upward going object so we will take it in '-' so gravity,g = -9.8 m/s^2

Height,s = ?

$<b><i><u> in attachment </b></i></u>$

so maximum height attained by ball = 122.5m

-----------------------------------------------

(2)now we will calculate the time by expression v= u + gt
0=49 + (-9.8)t
0 = 49 - 9.8 t
-49/-9.8=t
49*10/98 = t
10/2 = t
5s =t

[so time taken by ball to going upward = 5s

$<b><i><u>Note: the time the ball will take to go upward the same time it will take to come down .. so the time taken by ball to coming downward for top is also 5 s .And the total time travelled by ball during the journey is 5s + 5s =10s </b></i></u>$
___________
hope it helps you