Answer:
<h2>
2113 seconds</h2>
Explanation:
The general decay equation is given as 
, then;
where;
is the fraction of the radioactive substance present = 1/16
is the decay constant
t is the time taken for decay to occur = 8,450s
Before we can find the half life of the material, we need to get the decay constant first.
Substituting the given values into the formula above, we will have;
Half life f the material is expressed as 
Hence, the half life of the material is approximately 2113 seconds
Answer:
D. It has a low resistance and allows charges to move freely.
Explanation:
The high conductivity of copper allow charges to move freely without the need of too much force. The conductivity decreases with increase in resistance. Low resistance also means less heating of the conductors. This property of copper makes it ideal for use in the manufacture of electric cables and conductors for various gadgets.
Answer: 600N
Explanation:
Centripetal force is the force that causes a body to move in a circular path.
Centripetal force = MV²/r
M = 75kg v = 80m/s r = 0.80km = 800m
Substituting the values given in the formula;
F = 75 × 80²/800
F = 600N
The magnitude of the resultant force on the 75kg pilot is 600N.
I would say your answer to this question would be D
Parking lots with roads and concrete reduce infiltration. Infiltration is the process by which water penetrates the soil. Reducing the amount of water that enters the soil can eventually impact groundwater levels in some areas by decreasing it over time. Paved roads lead to increased surface runoff which increases the possibility of flooding in periods of heavy rainfall. This is known as urban flooding.
