A ball is sitting in a child's wagon and a child is holding the wagon's handle. The ball then rolls to the back of the wagon without anyone touching the ball directly. Which of the following statements according to Newton's first law of motion could describe the motion of the wagon?
Statement A: The wagon is moving forward, and the child suddenly increases the speed of the wagon.
Statement B: The wagon is moving backward, and the child suddenly slows it down.
Statement C: The wagon is at rest.
only A
only B
only C
A and C only
A and B only
According to Newton's first law of motion, an object will remain at rest or continue in a straight line at a constant speed unless acted upon by an external force. In this scenario, we can see that the ball rolls to the back of the wagon without anyone directly touching it. Therefore, we can conclude that the wagon itself must be in motion.
Statement A suggests that the wagon is moving forward, and the child suddenly increases its speed. This statement aligns with Newton's first law as the wagon was already in motion, and the child is applying an external force to make it go faster. So, Statement A is valid.
Statement B suggests that the wagon is moving backward, and the child suddenly slows it down. This statement contradicts Newton's first law because if the wagon is already in motion, it would require an external force to slow it down. However, the child is not applying any force to the wagon in this scenario. Therefore, Statement B is not valid.
Statement C suggests that the wagon is at rest. As we established earlier, the wagon must be in motion, so Statement C is not valid.
Based on this analysis, the correct answer is "A and C only."