Question

If an object is thrown vertically upward with speed 49ms-1 .How long does it take to complete upward journey? What is maximum height does it achieve

Answer 1

v = u + at
At, its highest point velocity v = 0; also during upward journey a = -g;
0 = 49 - 9.8*t 
t = 5 sec.
$v^{2} - u^{2}$ = 2as ;
0 - $49^{2}$ = -2*9.8*h
Maximum height h = 122.5m

Answer 2

v = u + at

At, its highest point velocity v = 0; also during upward journey a = -g;

0 = 49 - 9.8*t  

t = 5 sec.

v^{2}  -  u^{2}  = 2as ;

0 -  49^{2}  = -2*9.8*h

Maximum height h = 122.5m we can also approximate the value of 122.5 and write it as 120