Via half-life equation we have:

Where the initial amount is 50 grams, half-life is 4 minutes, and time elapsed is 12 minutes. By plugging those values in we get:

There is 6.25 grams left of Ra-229 after 12 minutes.
Answer:
M g H / 2 = M g L / 2 initial potential energy of rod
I ω^2 / 2 = 1/3 M L^2 * ω^2 / 2 kinetic energy attained by rod
M g L / 2 = 1/3 M L^2 * ω^2 / 2
g = 3 L ω^2
ω = (g / (3 L))^1/2
If the machine's mechanical advantage is 4.5, that means that
Output force = (4.5) x (Input force) .
We know the input force, and we need to find the output force. Rather than wander around the room looking at the floor while our hair smolders, let's try putting the numbers we know into the equation I wrote up there. OK ?
Output force = (4.5) x (Input force)
Output force = (4.5) x (800 N)
Now dooda multiplication:
<em>Output force = 3,600 N</em> .
That's exactly what the question asked for. So we're done !
Let, the temperature of Sun's surface = c
So, 5c = 30, 000
c = 30,000 / 5
c = 6,000
In short, Your Answer would be 6000
Hope this helps!
<h2>Answer:</h2>
<u>A) Increase the voltage by adding a bigger battery </u>
<h2>Explanation:</h2>
According to Ohm's law
V = IR
where V is voltage, I is current and R is the resistance. If we write the equation for resistance we would get
R= V / I
Here we can see that Voltage is directly proportional to Resistance so in order to keep the balance if we increase the resistance then we must increase the voltage to keep the current constant.