Answer:
9.43*10^3 year
Explanation:
For this question, we ought to remember, or know that the half life of carbon 14 is 5730, and that would be vital in completing the calculation
To start with, we use the formula
t(half) = In 2/k,
if we make k the subject of formula, we have
k = in 2/t(half), now we substitute for the values
k = in 2 / 5730
k = 1.21*10^-4 yr^-1
In(A/A•) = -kt, on rearranging, we find out that
t = -1/k * In(A/A•)
The next step is to substitite the values for each into the equation, giving us
t = -1/1.21*10^-4 * In(5.4/15.3)
t = -1/1.21*10^-4 * -1.1041
t = 0.943*10^4 year
I looked up the question and got D- a vacuum
<u>#2</u>
Use the formula ... Kinetic energy = (1/2) x (mass) x (speed)²
<u>#3 - a).</u>
sun => energy travels as electromagnetic waves => reaches Earth as
heat & light energy.
sun => absorbed in plants => eaten by animals => animals die =>
decay into oil in millions of years => we burn the oil to get the energy.
<u>#3 - b).</u>
food I ate for lunch => metabolized into glucose by my body
=> some of it burned in my muscles to generate energy for immediate needs
=> the rest of it stored as fat for future needs.
<u>#3 - c).</u>
flower pot rolls off the ledge => gravity does work on it all the way down,
producing the kinetic energy it has when it hits the floor.
<u>#3 - d).</u>
oil or natural gas is burned, releasing heat energy => energy is used
to generate electricity => electricity flows through cables from the
power generating plant to your home => hot plate plugged into the
wall => turns electrical energy back into heat energy => heat energy
is conducted into the bottom of the beaker, flows through the glass
to the inside surface => heat energy is conducted from the inside of
the glass to the water, which gets hotter as it absorbs more energy.
=============================
<u>Note:</u>
#1 on the sheet is wrong.
"Work = force x distance" that's correct
But 25-kg is the <em>mass</em> of the ball, <em>not </em>the gravitational <em>force </em>on it.
The force on it is (mass) x (gravity), called its "weight".
That's (25-kg) x (9.8 m/s²) = 245 kg-m/s² = 245 newtons .
So it doesnt get over heated ...
A cooling system<span> works by sending a liquid </span>coolant<span> through passages in the </span>engine<span>block and heads. As the </span>coolant<span> flows through these passages, it picks up heat from the </span>engine<span>. The heated fluid then makes its way through a rubber hose to the radiator in the front of the </span>car<span>.</span>
