Which scientist thought that the atom was the smallest particle in the universe?
a. niels bohr
b. john dalton
c. j. j. thomson
d. ernest rutherford

The scientist thought that the atom was the smallest particle in the universe is John Dalton. The answer is letter B. He established the atomic theory which consists of five; elements are made of extremely small particles called atoms, atoms of different element have different sizes, mass and physic – chemical properties, atoms cannot be divided further, destroyed or created, atoms can combine to form compounds and in chemical reaction, atoms can be combined, separated or rearranged. J.J. Thompson discovered the electrons in the atom. Ernest Rutherford discovered the half – life of an atom and Neils Bohr explain the quantum mechanics.

Is a  vector quantity  that refers to "the rate at which an object changes its position." imagine a person moving rapidly - one step forward and one step back - always returning to the original starting position. while this might result in a frenzy of activity, it would result in a zero velocity. because the person always returns to the original position, the motion would never result in a change in position. since velocity is defined as the rate at which the position changes, this motion results in zero velocity. if a person in motion wishes to maximize their velocity, then that person must make every effort to maximize the amount that they are displaced from their original position. every step must go into moving that person further from where he or she started. for certain, the person should never change directions and begin to return to the starting position.