Answer:
Explanation:
Given
Height of ceiling is 
Initial speed of Putty 
Speed of Putty just before it strike the ceiling is given by
where v=final velocity
u=initial velocity
a=acceleration
s=displacement



time taken by putty to reach the ceiling




Answer:
9155 years old
Explanation:
We use the following expression for the decay of a substance:

So we first estimate the value of k knowing that the half-life of the C14 is 5730 years:

so, now we can estimate the age of the artifact by solving for"t" in the equation:

which we can round to 9155 years old.
I think its E. the control rods are used to control <span>the fission rate of uranium and plutonium. Hope this helps!! </span>