I would first like to say that this equation is used in many different cases, and that this question is really broad. However, I do know one particular application of KE to motion.
First, you can't use lbs in the equation. It seems like you do not know the difference between mass and weight. Weight is the force of gravity pulling on you downwards. Mass is the measure of how much there is of something. Weight in Newtons can be calculated as $W=mg$ where W is the weight, m is the mass in kilograms, and g is the acceleration of gravity, which is 9.80 m/s on Earth, but is different on different planets. Therefore, weight is a variable quantity depending on where you are located (like whether you are on the Moon or on Earth), while mass is not variable.
One application of KE is in the work-energy principle. The work-energy principle states that the amount of work done on an object is equal to the change in kinetic energy. Work is defined as force through a distance - $W=Fd$ or for 2-D, $W=\vec F\cdot \vec s$. Mathematically, the work-energy principle can be stated as:
$$W = \Delta K$$
$$W=(1/2 mv_2^2)-(1/2mv_1^2) $$
If you know the forces acting upon an object along with the mass (although many times the mass is not needed as it cancels out) and the distance it travels, you can find its velocity. Or, given the necessary information, you can find the distance it travelled.
It seems I have misunderstood your question. First of all, it seems that there is a debate on whether or not pound is to be considered a mass. But for scientific purposes, pound is a force.
Second of all, you can put whatever units you want in the equation, as long as $m$ is in units of mass and $v$ is in units of velocity. You will still get an answer that is an energy. But to get units of Joules, the mass must be in kg, and the velocity must be in m/s.