The half-life is the time the sample takes to reduce to half of its original value. If we call
the initial mass of the sample, this means that after 1 half-life the mass will be
, after 2 half-lives the mass will be
, and so on..
Therefore, after x half-lives the mass of the sample will be
(1)
In our problem, the initial mass is
while the mass after x half-lives is
, so by using equation (1) we can find the value of x:
From which
And the correct answer is C).
Couldn’t really read or see the problem clearly, but from what I think I saw I would say B
It would be Mass and Time which would be the two fundamental units.
Earth's magnetic poles<span> are located near, but not quite exactly at, our planet's </span>geographic poles<span> (the "spin axis" on a globe). Compasses work as direction-finding devices because </span>Earth<span> has a </span>magnetic<span> field. The needle of a compass, itself a small bar </span>magnet<span>, points </span>in the<span> direction of the </span>magnetic pole<span>.</span>
Answer:
Approximately (assuming that .)
Explanation:
Let denote the force that this spring exerts on the object. Let denote the displacement of this spring from the equilibrium position.
By Hooke's Law, the spring constant of this spring would ensure that .
Note that the mass of the object attached to this spring is . Thus, the weight of this object would be .
Assuming that this object is not moving, the spring would need to exert an upward force of the same magnitude on the object. Thus, .
The spring in this question was stretched downward from its equilibrium by:
.
(Note that is negative since this displacement points downwards.)
Rearrange Hooke's Law to find in terms of and :
.