The equation relevant to this is:
S(t) = So + Vot - At²/2 <span>
</span>
<span>Therefore
we can create two equations:
<span>S(t) = 90 = So - 4t - 16.1t² -->
eqtn 1</span>
<span>S(t+2) = 10 = So - 4(t+2) - 16.1(t+2)² --> eqtn 2</span>
</span>
<span>Expanding
eqtn 2:
10 = So - 4t - 8 - 16.1(t² + 4t + 4)
10 = So - 4t - 8 - 16.1t² - 64.4t - 64.4
10 + 8 + 64.4 = So - 68.4t - 16.1t²
<span>82.4 = So - 68.4t - 16.1t² -->
eqtn 3</span></span>
<span>
Subtracting eqtn 1 by eqtn 3:</span>
90 = So - 4t - 16.1t²
82.4 = So - 68.4t - 16.1t²
=> 7.6 = 64.4t
t = 0.118 s
Therefore calculating for initial height So:<span>
<span>82.4 = So - 68.4(0.118) - 16.1(0.118)²
<span>So = 90.7 ft</span></span></span>
Answer:
this isn't physics this is german
Answer:
A(many people think that no energy or matter exists outside the universe)
Explanation:
Answer:
a) 4.94e9 J b) 1.07e10 J
Explanation:
The electric potential energy stored in a capacitor, expressed in terms of the value of the capacitance C, and the voltage between its terminals V, is as follows:

a) For the original capacitor, we can find directly U as follows:
U = 4.94*10⁹ J
b) Prior to find the electric potential energy of the upgraded capacitor, we need to find out the value of the capacitance C of this capacitor, which is identical to the original, except that has a different dielectric constant.
As the capacitance is proportional to the dielectric constant, we can write the following proportion:
ε₂ / ε₁ = 

Once calculated the new value of the capacitance, as V remains the same, we can find the electric potential energy for the upgraded capacitor as follows:

⇒ U = 1.07*10¹⁰ J