Physics Chapter 2
10) A 300-kg bear grasping a vertical tree slides down at constant velocity. The friction force between the tree and the bear is A) 3000 N. B) 30 N. C) 300 N. D) more than 3000 N.
A
14) According to Newton's law of inertia, a railroad train in motion should continue going forever even if its engine is turned off. We never observe this because railroad trains A) always have forces that oppose their motion. B) are much too heavy. C) must go up and down hills. D) move too slowly.
A
16) When a rocket ship accelerating in outer space runs out of fuel, it A) no longer accelerates. B) accelerates for a short time, then slows down to a constant velocity. C) accelerates for a short time, slows down, and eventually stops.
A
17) If no external forces are acting on a moving object, it will A) continue moving at the same velocity. B) move slower and slower until it finally stops. C) continue moving at the same speed.
A
1) Whereas Aristotle relied on logic in explaining nature, Galileo relied on A) logic also. B)experiment. C) patterns. D) mathematics.
B
11) A package falls off a truck that is moving at 30 m/s. Neglecting air resistance, the horizontal speed of the package just before it hits the ground is A) less than 30 m/s but larger than zero. B) about 30 m/s. C) zero. D) more than 30 m/s.
B
12) A truck is moving at constant velocity. Inside the storage compartment, a rock is dropped from the midpoint of the ceiling and strikes the floor below. The rock hits the floor A) ahead of the midpoint of the ceiling. B) exactly below the midpoint of the ceiling. C) behind the midpoint of the ceiling. D) More information is needed to solve this problem.
B
4) A sheet of paper can be withdrawn from under a container of milk without toppling it if the paper is jerked quickly. This best demonstrates that A) gravity tends to hold the milk carton secure. B) there is an action-reaction pair of forces. C) the milk carton has no acceleration. D) the milk carton has inertia. E) none of these
D
5) An object in mechanical equilibrium is an object A) having no acceleration. B) at rest. C) moving with constant velocity. D) all of these
D
18) Galileo's use of inclined planes allowed him to effectively A) slow down the acceleration of free fall. B) eliminate friction. C) eliminate the acceleration of free fall. D) increase the acceleration beyond that of free fall.
A
3) Galileo's interpretation of motion differed from Aristotle's in that Galileo emphasized A) time rates. B) the acceleration of free fall. C) the role of distance in describing motion. D) all of these E) none of these
A
6) When you stand at rest on a pair of bathroom scales, the readings on the scales will always A) add up to equal your weight. B) each equal your weight. C) each be half your weight.
A
8) A man weighing 800 N stands at rest on two bathroom scales so that his weight is distributed evenly over both scales. The reading on each scale is A) 400 N. B) 800 N. C) 200 N. D) none of these
A
9) The force of friction on a sliding object is 10 N. The applied force needed to maintain a constant velocity is A) 10 N. B) less than 10 N. C) more than 10 N.
A
2) The scientist to first introduce the concept of inertia was A) Copernicus. B) Galileo. C) Newton. D) Aristotle
B
7) Hang from a pair of gym rings and the upward support forces of the rings will always A) each be half your weight. B) add up to equal your weight. C) each equal your weight.
B
13) If your automobile runs out of fuel while you are driving, the engine stops but you do not come to an abrupt stop. The concept that most explains why is A) acceleration. B) gravity. C) inertia. D) resistance.
C
15) Whirl a rock at the end of a string and it follows a circular path. If the string breaks, the tendency of the rock is to A) continue to follow a circular path. B) Increase its speed. C) follow a straight-line path. D) revolve in a smaller circle.
C