Physics Chapter 2

What did Galileo discover in his legendary experiment on the Leaning Tower of Pisa? A. Galileo found that stones fall faster proportional to their weight. B. Galileo found that a heavier stone does not fall significantly faster than a lighter one. C. Galileo found that a heavier stone falls significantly faster than a lighter one. D. Galileo found that air resistance significantly slowed falling stones.

B. Galileo found that a heavier stone does not fall significantly faster than a lighter one.

What did Galileo discover about moving bodies and force in his experiments with inclined planes? A. Bodies rolling down an inclined plane slowed down. B. In the absence of a retarding force, a body will keep moving at a constant speed in a straight line forever. C. Bodies rolling up an inclined plane sped up. D. Bodies rolling down a steep inclined plane starting at a given height rolled up a gently inclined plane to a higher height.

B. In the absence of a retarding force, a body will keep moving at a constant speed in a straight line forever.

If you toss a coin straight upward in a train that is speeding up quickly, the coin will land A. in front of you. B. behind you. C. in your hand.

B. behind you.

What type of path does a moving object follow in the absence of a force? A. It moves in a straight line and eventually slows to a stop. B. It follows a parabolic trajectory in the absence of a force. C. It follows a circular path in the absence of a force. D. It continues to move in a straight line at a constant speed.

D. It continues to move in a straight line at a constant speed.

A bowling ball at rest is in equilibrium. Is the ball in equilibrium when it moves at constant speed in a straight-line path? A. Yes, the bowling ball is in equilibrium because ΣFΣF = 0. B. The bowling ball is not in equilibrium because ΣFΣF = -mg. C. The bowling ball is not in equilibrium because it is moving. D. The bowling ball is not in equilibrium because the wood of the bowling alley exerts an upward force on the ball.

A. Yes, the bowling ball is in equilibrium because ΣFΣF = 0.

You tell your friend about the neat tablecloth trick that Dr. Hewitt demonstrated. Your friend tries to repeat this trick at home and later complains to you that it failed. Which of the following is most likely the reason that it failed? A. Your friend pulled the tablecloth too slowly. B. The items placed on the tablecloth were too light. C. Your friend is too clumsy. D. Your friend pulled the tablecloth too quickly.

A. Your friend pulled the tablecloth too slowly.

Which of the following are in equilibrium? (You may select more than one answer.) A. A ball falling to the ground B. A car travelling at a steady speed of 60 mph on a straight road C. A car going in a straight road but slowing down for a traffic light D. A ball sitting on table E. A car turning a curve at a constant 30 mph speed

B. A car travelling at a steady speed of 60 mph on a straight road D. A ball sitting on table

What does it mean to say something is in mechanical equilibrium? A. An object in mechanical equilibrium is always in motion. B. An object in mechanical equilibrium experiences a zero net force. C. An object in mechanical equilibrium must experience no forces. D. An object in mechanical equilibrium experiences a net force twice its weight.

B. An object in mechanical equilibrium experiences a zero net force.

What is the net force on a cart that is pulled to the right with 100 pounds of force and to the left with 30 pounds of force? A. The net force is zero. B. The net force is 70 pounds to the right. C. The net force is 130 pounds. D. The net force is 70 pounds to the left.

B. The net force is 70 pounds to the right.

What is the net force on an object in either static or dynamic equilibrium? A. The net force is vertical for static equilibrium and horizontal for dynamic equilibrium. B. The net force is zero. C. The net force is zero for static equilibrium and greater than zero for dynamic equilibrium. D. The net force is equal and opposite to the weight of the object.

B. The net force is zero.

When Dr. Hewitt pulls the tablecloth, what happens to the items on the tablecloth? A. They move horizontally in the opposite direction from the tablecloth. B. They tend to stay where they were. C. They move vertically upward. D. They move horizontally in the same direction as the tablecloth.

B. They tend to stay where they were.

Consider a book that weighs 15 N at rest on a flat table. How many newtons of support force does the table exert on the book? A. 30 newtons up B. 15 newtons down C. 15 newtons up D. 0 newtons

C. 15 newtons up

The scaffold is in mechanical equilibrium. The forces by the two painters, the weight of the scaffold, and the tension by the left rope on the scaffold are as shown. How much is the tension by the right rope? A. 800 N B. None of the above. C. 500 N D. 300 N

C. 500 N

What class of motion did Aristotle attribute to the Moon? A. Violent B. Continuous C. Natural D. At rest

C. Natural

If you push on a crate with a horizontal force of 100 N and it slides at constant velocity, what is the magnitude and direction of the frictional force acting on the crate? A. The frictional force has nothing to do with you pushing on the crate. B. The frictional force on the crate is zero newtons. C. The frictional force on the crate is 100 N opposite the direction of motion. D. The frictional force on the crate is 100 N in the same direction as the direction of motion.

C. The frictional force on the crate is 100 N opposite the direction of motion.

What is the resultant of a pair of one pound forces at right angles to each other? A. The resultant is a force of 1.0 pound in a direction bisecting the angle between the two vectors. B. The resultant is a force of 2.0 pounds in a direction bisecting the angle between the two vectors. C. The resultant is a force of 1.41 pounds in a direction bisecting the 90-degree angle between the two vectors. D. The resultant is zero force.

C. The resultant is a force of 1.41 pounds in a direction bisecting the 90-degree angle between the two vectors.

When Dr. Hewitt pulls the tablecloth, why do the items on the tablecloth do what they do? A. Friction with the tablecloth is keeping them there. B. Friction with the table is keeping them there. C. Their inertia is sufficient to keep them there. D. They are attached to the tablecloth.

C. Their inertia is sufficient to keep them there.

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

C. half your weight

What two classes of motion did Aristotle advocate? A. Vertical motion and horizontal motion B. Propelled motion and passive motion C. Earthly motion and heavenly motion D. Natural motion and violent motion

D. Natural motion and violent motion

What is the net force on a bag pulled down by gravity with a force of 18 newtons and pulled upward by a rope with a force of 18 newtons? A. The net force is 18 newtons. B. The net force is 36 newtons. C. The net force is 25 newtons. D. The net force is zero newtons.

D. The net force is zero newtons.

Stand next to a wall that travels at 30 km/s relative to the Sun. With your feet on the ground, you also travel at the same 30 km/s. Do you maintain this speed when your feet leave the ground? What concept supports your answer? A. When you jump, your velocity relative to the Sun goes to zero because the forces on you are in equilibrium. B. When you jump, your velocity relative to the Sun changes to -30 km/s so that your velocity relative to the wall is zero, because the forces on you are in equilibrium. C. When you jump, your velocity relative to the Sun drops to zero due to inertia. D. When you jump, you continue to move at 30 km/s due to your inertia.

D. When you jump, you continue to move at 30 km/s due to your inertia.

When you stand at rest on a bathroom scale, how does your weight compare with the support force from the scale? A. The support force from the scale is half your weight. B. The support force from the scale is twice your weight. C. Your weight is equal in magnitude and in the same direction as the support force from the scale. D. Your weight is equal in magnitude and opposite in direction to the support force from the scale.

D. Your weight is equal in magnitude and opposite in direction to the support force from the scale.

The earth moves about 30 km/s relative to the sun. When you jump upward in front of a wall, the wall does not slam into you. This is because the wall A. has negligible inertia compared with the Sun. B. moves in an opposite direction to you. C. has too little gravity to influence you. D. and you are moving at the same horizontal speed before, during, and after your jump.

D. and you are moving at the same horizontal speed before, during, and after your jump.

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 concept of momentum. D. discover the property called inertia.

D. discover the property called inertia.

If while riding in a smooth-riding train, you toss a coin upward, the coin will normally land ______. A. off to the side of your location when you toss the coin B. behind you C. in front of you D. in your hand

D. in your hand

A cart is pulled by a pair of 20 N forces that are perpendicular to each other, one to the West, the other to the South. What is the net force on the cart? A. 36 N B. 0 N C. 20 N D. 40 N E. 28 N

E. 28 N