Question

a body thrown vertically upward returns to the earth in 3sec
what was the initial velocity of the body? what height did the body reach?
neglect the resistance of air.
The answer after solving is 14.7m/s and
11m. please tell me how the answer is arrived.

Answer 1

Vf = Vo + gt,
a. Vo=Vf - gt = 0 - (-9.8)(3/2) = 14.7m/s.

b. h = Vo*t + 0.5gt^2,
h=14.7*1.5 + 0.5*(-9.8)(1.5)^2 =11.03m.

Answer 2

Vf=Vi+at
Om/s=Vi+(9.8m/s²)(3s)
Vi=29.4m/s

d=Vit+(0.5)at²
d=29.4m/s(3s)+(0.5)(3s)²
d=88.2m+44.1m
d=132.3m