University:
Boston University
Course:
CAS PY 105 | Physics 1
Academic year:

2024
Views:

443

Pages:

1
Author:

Autumn Campos

Homework: Newton’s First Law In class, you learned Newton’s First Law, which states: Unless acted on by a net force, an object at rest will remain at rest, and an object moving will keep moving at constant velocity. Or to put it differently: an object will keep doing what it’s doing unless there’s a net force acting on it. Using Newton’s First Law, answer the following multiple choice questions: 1. An object following a straight-line path at constant speed… a. has a net force acting on it in the direction of motion. b. has no forces acting on it. c. must be moving in a vacuum. d. has zero acceleration. 2. A piece of paper can be pulled from under a tall vase full of water without toppling it over if the piece of paper is jerked quickly. This is because… a. the vase is at rest to start with, so it resists the quick motion of the paper. b. the vase is much heavier than the paper. c. the paper is very thin. 3. There is a frictional force of 10 Newtons on a box sliding across a tabletop. In order to keep the box moving at a constant velocity, you would have to supply a force of… a. Nonsence! No force is required to keep the box moving. b. slightly less than 10 Newtons. c. exactly 10 Newtons. d. slightly more than 10 Newtons. 4. The reason a penny thrown straight up inside a bus moving a constant velocity will return to your hand is… a. the penny is pushed along by the air in the bus. b. the penny has no net force acting on it parallel to the ground. c. It won’t! You must throw it forward slightly; otherwise it lands behind you. d. No forces at all are acting on the penny.