Use your imagination to Consider two tennis balls on a flat table. The two balls touch each other and are at rest. Which of the following equations is Newton's law in the vertical direction for the tennis ball closer to the observer? Recall that we use N for normal forces, F for contact forces between the two balls, and W for weights.
1. F+W=0 2.F-W=0 3.N+W=0 4.N-W=0 5.N-F=0
no point will be awarded for the answer with no explanation. only answers with explanations will receive the bonus points