Question

An object is throw vertically upwards and rises to a heigh of 25 m . Calculate the velocity with which the object was thrown . Also find the time taken to reach the highest point . ( take g = 9.8 m/s^2)​

Answer 1

Explanation:

vf=0 as the object will stop at a point for amoment before coming down

h=25m

g=9.8m/s2

t=?

vi=?

For initial velocity using 3rd equation of motion

2gh=vf2-vi2

By putting values

2(-9.8)(25)=(0)2-vi2

-19.6(25)=-vi2

490=vi2

Taking square root

22.136=vi

now for 't'using 1st equation of motion

vf=vi+at

0=22.136-9.8(t)

-22.136=9.8t

t=22.136/9.8

t=2.26s

so the initial velocity is 22.136m/s and time taken is 2.26s

here we have taken 'g' as negative as object is going upward

hope you understood it.......