it all depends on Region and how long they have been there some minerals crush faster then some others so some might only take a few thousand while others might take millions
Answer:
1050 possible selections
Explanation:
<em>Number of red balls = 7</em>
<em>Number of blue balls = 10</em>
<em>Let blue balls be B and red balls be R</em>
<em>four balls are to be selected. At least three must be blue.</em>
the first combination is 4blue 0red
second combination is 3blue 1red
(10C4*7C0 + 10C3*7C1)
210 *1 +120 *7
210+840
=1050 possibilities
Answer:
The answer is 3.0 V
Explanation:
the formula of the potential due to a non-conductive sphere with a uniform charge at a point at a distance x from the center of the sphere is equal to:
V1 = (2*π*k*ρ*(3*r^2 - x^2))/3
where
ρ = volume charge density = 100 nC/m^3
x = distance from center = 0
r = radius = 10 cm = 0.1 m
Thus:
V1 = (2*π*k*ρ*3*r^2)/3
for x = 4 cm = 0.04 m, we have:
V4 = (2*π*k*ρ*(3*r^2 - (0.04^2))/3 = (2*π*k*ρ*(3*r^2 - 0.0016))/3
The difference between both equations:
V1 - V4 = (2*π*k*ρ*3*r^2)/3 - (2*π*k*ρ*(3*r^2 - 0.0016))/3
V1 - V4 = (2*π*k*ρ*0.0016)/3 = (2*π*9x10^9*100x10^-9*0.0016)/3 = 3.02 V = 3 V
