Question

a ball is thrown vertically upwards with a velocity of 20m/s. What's the maximum height after 30secs

Answer 1

let us find out at what time the ball will reach its maximum height

at maximum height

v=0 m/s

u=30 m/s

a=-10 m/s² (value of g approximately and - sign because directions are opposite)

v=u+at

0=30-10t

t=3 seconds

now,

s=ut+(1/2)at²

s=30*3+(1/2)*-10*9

s=90-45

s=45m

45 m is its maximum height which will be obtained in 3 seconds and the ball will come to rest before 30 seconds