Question

A stone thrown from the top of a building is
given an initial velocity of 20.0 m/s straight
upward. Determine the time in seconds at
which the stone returns to the height from
which it was thrown.
g = 9.8 m/sec2
A: 3.45
B: 3.46
C: 4.52.
D: 4.08​

Answer 1

Answer:

4.08s

Explanation:

u = 20m/s

a = -10m/s²

s = 0

USING THE 2ND EQUATION OF MOTION:

s = ut + ½at²

0 = 20t - 4.9t²

4.9t = 20

t = 4.08s