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.
Answer:
Explanation:
Momentum conservation

Kinetic energy conservation

Solve the system
Answer:
Vapors
Explanation:
We take into account that all the energy from the lightning has been transformed into steam.

We calculate the amount of energy required by water to convert into steam.



From the lightning we received
of energy, out of which
has been used to convert the water into steam.
Energy left = 
We use this energy to convert steam into vapors.


With this temperature, we can easily interpret that the vapors will be dissociated in hydrogen and oxygen particles.
Move from higher to lower energy levels
First we need to convert the angular speed from rpm to rad/s. Keeping in mind that


the angular speed is

And so now we can calculate the tangential speed of the child, which is the angular speed times the distance of the child from the center of the motion: