CONCEPTUAL QUESTIONS NEWTON’S FIRST LAW: 2-1-2 If you were in a spaceship and fired a cannonball into space, how much force would have to be exerted on the ball to keep it moving once it has left the spaceship? Many automobile passengers have suffered neck injuries when struck by cars from behind. How does 's law of inertia apply here? How do headrests help to guard against this type of injury? Suppose you place a ball in the middle of a wagon, and then accelerate the wagon forward. Describe the motion of the ball relative to the ground. Describe its motion relative to the wagon. If an elephant were chasing you, its enormous mass would be most threatening. But if you zigzagged, its mass would be to your advantage. Why? Two closed containers look the same, but one is packed with lead and the other with a few feathers. How could you determine which has more mass if you and the containers were orbiting in a weightless condition in outer space? A metal ball is put into the end of the tube indicated by the arrow. The ball is then shot out of the other end of the tube at high speed. Pick the path the ball will follow after it exits the tube. Note you are looking down on these tubes, they are not vertical. – How much support does a table exert on a book that weighs 15 N when the book is placed on the table? What if a hand pushes down on the book with a force of 20 N? What if a rope lifts up on the book with a force of 10 N? (The hand is no longer there.) When a 100 N bag of nails hangs motionless from a single vertical strand of rope, how many newtons of tension are exerted in the strand? What if the bag is supported by four vertical strands? An object weighs 98 N on How much does it weigh on Planet X where the acceleration due to gravity is 6 m/s2?
CONCEPTUAL QUESTIONS NEWTON’S FIRST LAW: 2-1-2 If you were in a spaceship and fired a cannonball into space, how much force would have to be exerted on the ball to keep it moving once it has left the spaceship? Many automobile passengers have suffered neck injuries when struck by cars from behind. How does 's law of inertia apply here? How do headrests help to guard against this type of injury? Suppose you place a ball in the middle of a wagon, and then accelerate the wagon forward. Describe the motion of the ball relative to the ground. Describe its motion relative to the wagon. If an elephant were chasing you, its enormous mass would be most threatening. But if you zigzagged, its mass would be to your advantage. Why? Two closed containers look the same, but one is packed with lead and the other with a few feathers. How could you determine which has more mass if you and the containers were orbiting in a weightless condition in outer space? A metal ball is put into the end of the tube indicated by the arrow. The ball is then shot out of the other end of the tube at high speed. Pick the path the ball will follow after it exits the tube. Note – you are looking down on these tubes, they are not vertical. How much support does a table exert on a book that weighs 15 N when the book is placed on the table? What if a hand pushes down on the book with a force of 20 N? What if a rope lifts up on the book with a force of 10 N? (The hand is no longer there.) When a 100 N bag of nails hangs motionless from a single vertical strand of rope, how many newtons of tension are exerted in the strand? What if the bag is supported by four vertical strands? An object weighs 98 N on How much does it weigh on Planet X where the acceleration due to gravity is 6 m/s2?
2-1-2_inertia.docx