Conceptual Physics Ch 2

kilometer

1000 meters.

A cart is pushed to the right with a force of 15 N while being pulled to the left with a force of 20 N. The net force on the cart is A) 5 N to the left. B) 5 N to the right. C) 25 N to the left. D) 25 N to the right.

A) 5 N to the left. Two forces are in opposite directions, so they subtract. The direction is determined by the direction of the larger force.

When you hang from a pair of gym rings, the upward support forces on the rings will always A) add up to your weight. B) each be half your weight. C) each equal your weight

A) add up to your weight.

When you stand at rest on a pair of bathroom scales, the readings on the scales will always A) always add up to your total weight. B) each equal your entire weight. C) always be half your weight.

A) always add up to your total weight.

To rip a piece of toilet paper off of the roll, you need to pull it __________. Video: Toilet Paper Roll A) quickly B) slowly

A) quickly

A sheet of paper can be withdrawn from under a container of milk without toppling it if the paper is jerked quickly.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) the milk carton has inertia. B) gravity tends to hold the milk carton secure. C) there is an action-reaction pair of forces. D) the milk carton has no acceleration.

A) the milk carton has inertia.

The equilibrium rule, F = 0, applies to A) vector quantities. B) scalar quantities. C) Both of the above. D) None of the above.

A) vector quantities. Explanation: Vector addition accounts for + and - quantities. So, two vectors in opposite direction can add to zero.

km

Abbreviation for kilometer.

force

Any influence that tends to accelerate an object; a push or pull; measured in newtons. Force is a vector quantity.

normal

At right angles to, or perpendicular to. A normal force acts at right angles to the surface on which it acts. In optics, a normal defines the line perpendicular to a surface about which angles of light rays are measured.

How much does one kilogram weight? Video: Definition of a Newton A) 1 Newton B) 9.8 Newtons C) 1 kilogram D) 1 pound

B) 9.8 Newtons

The scientist to first introduce the concept of inertia was A) Aristotle. B) Galileo. C) Copernicus D) Newton.

B) Galileo.

Whereas Aristotle relied on logic in explaining nature, Galileo relied on A) patterns. B) experiment. C) logic also D) mathematics.

B) experiment.

When you stand on two bathroom scales with one foot on each scale and with your weight evenly distributed, each scale will read A) your weight. B) half your weight. C) zero. D) more than your weight.

B) half your weight.

The force of friction on a sliding object is 10 N. The applied force needed to maintain a constant velocity is A) more than 10 N. B) less than 10 N. C) 10 N.

C) 10 N

A 300-kg bear grasping a vertical tree is stationary. The friction force between the tree and the bear is A) more than 3000 N. B) 300 N. C) 3000 N D) 30 N

C) 3000 N

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) 200 N B) 800 N. C) 400 N D) not enough information to answer.

C) 400 N

A bowling ball is in equilibrium when it A) is at rest. B) moves steadily in a straight-line path. C) Both of the above. D) None of the above.

C) Both of the above.

Why does an anvil have a lot of inertia? Video: Inertia of an Anvil A) It is stationary. B) It is big. C) It has a lot of mass.

C) It has a lot of mass.

What is the name of the force responsible for keeping a rolling cylinder moving across a table with a steady speed? Video: Inertia of a Cylinder A) Inertia B) Rolling force C) There is no force responsible.

C) There is no force responsible.

Why do the dinner settings stay on the table when the tablecloth is pulled out from underneath very quickly? Video: The Old Tablecloth Trick A) Magnetic forces keep the settings stationary. B) No forces act on the dinner pieces while the tablecloth is being pulled out. C) They resist motion because of inertia.

C) They resist motion because of inertia.

An object in mechanical equilibrium is an object A) having no acceleration. B) moving with constant velocity C) all of these D) at rest.

C) all of these

You are riding in a van at a steady speed and toss a coin up. Where will the coin land? A) behind you B) ahead of you C) back in your hand D) There is not enough information.

C) back in your hand.

The use of inclined planes for Galileo's experiments helped him to A) eliminate the acceleration of free fall. B) discover the concept of energy. C) discover the property called inertia. D) discover the concept of momentum.

C) discover the property called inertia. Note that inertia is a property of matter, not a reason for the behavior of matter.

You are pushing a crate at a steady speed in a straight line. If the friction force is 75 N, how much force must you apply? A) more than 75 N B) less than 75 N C) equal to 75 N D) not enough information

C) equal to 75 N and in opposite direction of.

Galileo's discredited Aristotle's interpretation of motion using A) the motions of planets around the Sun. B) the role of push and pull in describing motion. C) the acceleration of free fall.

C) the acceleration of free fall.

net force

Combination of all the forces that act on an object.

normal force

Component of support force perpendicular to a supporting surface. For an object resting on a horizontal surface, it is the upward force that balances the weight of the object.

What is the net force acting on the box? A) 15 N to the left B) 15 N to the right C) 5 N to the left D) 5 N to the right

D) 5 N to the right

law of inertia

Every object continues in a state of rest, or of uniform speed in a straight line, unless acted on by a nonzero net force.

Newton's first law of motion

Every object continues in a state of rest, or of uniform speed in a straight line, unless acted on by a nonzero net force. Also known as the law of inertia.

scale

In music, a succession of notes of frequencies that are in simple ratios to one another.

equilibrium rule

On an object or a system of objects in mechanical equilibrium, the sum of forces equals zero.

inertia

Sluggishness or apparent resistance of an object to change its state of motion. Mass is the measure of inertia.

mechanical equilibrium

State of an object or system of objects for which any impressed forces cancel to zero and no acceleration occurs and when no net torque exists.

support force

Upward force that balances the weiight of an object on a surface.

Equilibrium

a state of no change with no net force acting. Equilibrium means no change in motion, so there are two options: Static equilibrium - If at rest, it continues at rest. example: hockey puck at rest on slippery ice. Dynamic equilibrium - If in motion, it continues at a steady rate in a straight line. example: hockey puck sliding at constant speed on slippery ice.