NOTE: The following questions are not part of any homework assigned. This is part of finding extra concept-related questions to help me study for my physics unit test. The problem statement, all variables and given/known data I have conceptual questions, not problems. I'll provide sufficient evidence that I've attempted to think about them. 1. A boy seems to fall backward in an accelerating bus. What property does this illustrate? I'm honestly swaying between the law of inertia and the third law. I'm thinking law of inertia because the boy is resisting, then "non resisting" a change in motion... But I'm thinking third law because the bus is moving forward and the boy is falling backward. (Sorry if this is an obvious question.) 2. What is the difference between inertial and noninertial reference frames? Just a question about vocabulary terms. I know that inertia is the tendency for objects to resist a change in motion. Would non-inertial mean that the object doesn't experience as much inertia, or no inertia at all? 3. A fisherman stands in a boat that is moving forward toward a beach. What happens to him when the boat hits the beach? Thinking that it may have to do with Newton's third law (i.e. when boat hits dock, fisherman falls back)? Is this a trick question or more obvious than it seems :D ? 4. A passenger sits in a stationary train. There are some objects on a table: an apple, a box of candy, and a can of soda. What happens to all these objects with respect to the passenger when the train accelerates forward? Of course the objects fall backward, but why? Is it the third law acting again? As the train accelerates forward, the passenger and his objects move back.... BUT: "what happens to all these objects with respect to the passenger"; is this a trick question, leading me to believe that the passenger is facing the back, instead of the front of the bus? 5. A rock is thrown vertically upward and stops for an instant at its highest point. Is the rock in equilibrium at this point? Are there forces acting on it? This one threw me off - the object isn't moving, but there is a force of gravity/air resistance? This led me to the next question.... 6. Is it possible for an object to have a zero acceleration and zero velocity when only one force acts on it? Not sure if it's completely relevant, but I remember a question that asked if an object could have a zero velocity and non-zero acceleration, and found that at an object's peak, the acceleration would be non-zero and the velocity would be 0. Now on to this question, I'm thinking as hard as I can to think of an example in which there is zero acceleration/velocity with only ONE force acting on it. All I can think of is if the force is equal to 0, but this obviously wouldn't be possible 7. Two boys are pulling a spring scale in opposite directions. What is the reading of the spring scale if each boy applies a force of 50N? Our class hasn't really covered spring forces/Hooke's laws other than in free-body diagrams, but I'm still curious about this. 50+50=100N?