Answer:
D) the decay rates of radioactive uranium and lead
Explanation:
As we know that when she found the substance it must have some fixed ratio of radioactive uranium and Lead in that substance.
Here since Uranium is radioactive substance so it will continuously convert into Lead and this ratio will change with time
So here we can say that the ratio of radioactive uranium and lead will depend on its decay rate
now to find the age of the substance we can find the present ratio of lead and uranium in that substance and then compare it with freshly prepared substance.
so by the formula
we can find the age of the sample
As kinetic energy increases, substance temperature increases
Answer:
Zero
Explanation:
Average velocity is given by:

where
d is the displacement of the trip
t is the time it takes for the trip to complete
In this problem, the net displacement of the swimmer is zero. In fact:
- First, he swims 30.0 m in the north direction
- Then, he travels back (-30.0 m) in the south direction, to the starting position
Since the final position is equal to the starting position, the displacement is zero:
d = 0
And therefore, the average velocity is also zero.
Answer:
660V
Explanation:
V=IR
V=11×60
=660V
hope this helps
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