A skydiver jumps from an airplane and accelerates toward the ground. His velocity can be modeled by the function v(t)=1000t5t+8, where v(t) is the velocity in feet per second, and t represents time in seconds. Due to air resistance, there is a limiting velocity the skydiver will not exceed, called the "terminal velocity". At terminal velocity, the velocity does not continue to increase. What is the terminal velocity? Justify your answer.