The sum of potential energy<span> and kinetic </span><span>energy.
Hope I helped!</span>
Yes, yes, we know all of that. It certainly took you long enough to
get around to asking your question.
If
a = (14, 10.5, 0)
and
b = (4.62, 9.45, 0) ,
then, to begin with, neither vector has a z-component, and they
both lie in the x-y plane.
Their dot-product a · b = (14 x 4.62) + (10.5 x 9.45) =
(64.68) + (99.225) = 163.905 (scalar)
I feel I earned your generous 5 points just reading your treatise and
finding your question (in the last line). I shall cherish every one of them.
Answer:
Initial velocity will be 1.356 m/sec
Explanation:
Let the initial speed = u
Angle at which rubber band is launched = 37°
Horizontal component of initial velocity 
Time is given as t = 1.20 sec
Distance in horizontal direction = 1.30 m
We know that distance = speed × time
So time 


So initial velocity will be 1.356 m/sec