How is an experiment is actually conducted

Ahypothesis is? close agreement by competent observers of observations of the same phenomena. a guess that has been tested over and over again and always found to be true. an educated guess that has yet to be proven by experiment. the long side of a right triangle. a synthesis of a large collection of information that includes guesses.

When the force acting on an object points at least partially in the direction of the motion the work done is considered to be negative

Can anybody me with this? ? (picture included.)