4. (a) State Newton's second law of motion. (b) Explain how it introduces the concept of mass. (c) Describe an experiment that could falsifyi 5. (a) State Newton's 3rd law of motion. (b) A child has built a snowman on a frozen lake. At a particular moment the child, after running toward the snowman, tackles the snowman. Which pairs of the following forces are related according to Newton's third law of motion? i. The force of the child on the snowman ii. The gravitational force of the child on the earth ili. The gravitational force of the earth on the showman iv. The gravitational force of the earth on the child v. The force of the snowman on the child vi. The gravitational force of the snowman on the earth (c) Since the snowman does not move up or down (meaning the component of its velocity in the up/down direction is the constant zero) according to Newton's first law of motion, the sum of forces on the snowman in the up direction is zero. To spell that out, the sum of the gravitational force of the earth on the snowman (which is directed downward) and the force of the frozen lake on the snowman (which is directed upward) is zero. Is this zero sum of forces guaranteed by Newton's third law of motion