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students in ms. sawyer's class built balloon cars. the balloon car works this way. as the gas in the balloon is released, the car moves in the opposite direction. the bigger the balloon initially, the farther the car moves. this balloon car is a good model of newton's
a) first law of motion. b) second law of motion. eliminate c) third law of motion. d) law of gravitational attraction.

Third law of motion

Explanation:

Students in Ms. Sawyer's class built balloon cars. The balloon car works this way.

This balloon car is a good model of Newton's third's law of motion. According to this law, for every action, there exists an equal and opposite reaction. Both action and reaction occur in pair. The direction of force acting on one object is in the opposite direction to the direction of force on other object.      

In this case, as the gas in the balloon is released, the car moves in the opposite direction. This is due to newton's third law of motion. Here, gas in the balloon is action force and the motion of car in opposite direction is reaction force.

Hence, the correct option is (c) " third law of motion ".