The penny hits the ground after C) 14.1 s.
Explanation:
The motion of the penny is a free fall motion (acted upon gravity only), so it is a motion at constant acceleration, therefore we can use the following suvat equation:
[tex]s=ut+\frac{1}{2}at^2[/tex]
where
s is the vertical displacement
u is the initial vertical velocity
a is the acceleration
t is the time
For the penny in this problem, chosing downward as positive direction:
u = 2.0 m/s
s = 1000.0 m (the heigth of the building)
[tex]a=g=9.8 m/s^2[/tex] (acceleration of gravity)
Substituting into the equation,
[tex]1000 = 2.0t +\frac{1}{2}(9.8)t^2\\4.9t^2+2.0t-1000=0[/tex]
Solving the equation for t, we find:
[tex]t=\frac{-2.0 \pm \sqrt{(2.0)^2-(4)(4.9)(-1000)}}{2(4.9)}[/tex]
which has two solutions:
t = -14.5 s
t = 14.1 s
We neglect the negative solution since it has no physical meaning, therefore the penny hits the ground after
C) 14.1 s.
Learn more about free fall motion:
brainly.com/question/1748290
brainly.com/question/11042118
brainly.com/question/2455974
brainly.com/question/2607086
#LearnwithBrainly
