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:
1.29 kg
Explanation:
As we know that
W= FS
1.56 = F (0.78)
F= 1.56/0.78
F= 2 N
Now, According to the definition of Force
F= ma
then
m= F /a
m= 2 / 1.54
m = 1.29 kg
Because the information cant be out of the investigation
B
Assume north and east as two sides of a right angled triangle. magnitude of the distance is then given by the length of the hypotenuse which is 
where a = 1.2 km north
and b = 1.6 km east
magnitude = 2 km
Direction is given by the angle between them, that is atan(a/b) = 36.86 deg north of east = 53.1 deg east of north.
