I'm not sure what your question is. But, the half life is the amount of time required for half the material to decay. For U238 this is 4.5 billion years, whilst for Fr-223 (Francium) its about 22 minutes. To calculate the time for something to decay you need to use the equation:
Mass (after time t) = Mass (initial) * (0.5)^(time/half life)
Hope this helps
Oil <span>must be mined from underground
Oil is NOT a renewable resource
Oil does NOT release more toxins than coal
Oil also is NOT easily replenished
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Our year would now be 2.8 times longer, we would also be receiving only 1/4 of the energy from the sun that we currently do. This means that we’d now be out beyond the orbit of Mars and right at the edge of the asteroid belt, and things would rapidly get very cold with temperatures expected to drop by around 50 degrees Celsius on average, and that’s with our current atmospheric composition which would not be stable in the new conditions. And also, any living thing on earth would die.
Answer:
Tangential
Explanation: This is a kind of force which act on a moving body in such a way that it is curved in the direction of the path of the body. This implies that when the velocity of the object is positive, the acceleration will be negative.
