Answer:
460.52 s
Explanation:
Since the instantaneous rate of change of the voltage is proportional to the voltage in the condenser, we have that
dV/dt ∝ V
dV/dt = kV
separating the variables, we have
dV/V = kdt
integrating both sides, we have
∫dV/V = ∫kdt
㏑(V/V₀) = kt
V/V₀ = 
Since the instantaneous rate of change of the voltage is -0.01 of the voltage dV/dt = -0.01V
Since dV/dt = kV
-0.01V = kV
k = -0.01
So, V/V₀ = 
V = V₀
Given that the voltage decreases by 90 %, we have that the remaining voltage (100 % - 90%)V₀ = 10%V₀ = 0.1V₀
So, V = 0.1V₀
Thus
V = V₀
0.1V₀ = V₀
0.1V₀/V₀ = 
0.1 = 
to find the time, t it takes the voltage to decrease by 90%, we taking natural logarithm of both sides, we have
㏑(0.01) = -0.01t
So, t = ㏑(0.01)/-0.01
t = -4.6052/-0.01
t = 460.52 s
Answer:

Explanation:
Since the object is under a circular motion, according to Newton's second law, when the object is at the top of the circle we have:

Where
is the centripetal force and is given by:

Replacing and solving for T:

Answer:
360 ÷ 4 = 90
Example
A 360° circle is cut into 4 peaces in the form of + or × . It's one side is called 90°
Answer: A, B, and D,
C is incorrect because continental drift takes several centuries to move the tectonic plates witch is not an immediate impact leaving you with A,B, and D.