Final answer:
The next appropriate task for Newton would be to analyze the motion of the apple using the principles of physics, measuring time and distance to formulate mathematical equations.
Step-by-step explanation:
After observing the apple fall from the tree, the next appropriate task for Newton as part of his scientific investigation would be to analyze the motion of the apple using the principles of physics. He would likely measure the time it takes for the apple to fall, as well as its distance from the tree. By applying his understanding of gravitational force and motion, Newton could then formulate mathematical equations to describe the apple's motion, such as using the equation d = 1/2 * g * t^2, where d is the distance, g is the acceleration due to gravity, and t is the time.
Learn more about Newton's scientific investigation on the motion of an apple