Chapter 2

Newton’s First Law of Motion—Inertia

Aristotle and his followers for many centuries thought Earth was at rest at

the center of the universe because

a. humans experience no sensation of a moving Earth.

b. Earth rotates about its axis.

c. Earth moves in a perfect circle.

d. Earth moves in an elliptical path about the Sun.

Aristotle and his followers for many centuries thought Earth was at rest at

the center of the universe because

a. humans experience no sensation of a moving Earth.

b. Earth rotates about its axis.

c. Earth moves in a perfect circle.

d. Earth moves in an elliptical path about the Sun.

Science greatly advanced when Galileo favored

a. philosophical discussions over experiment.

b. experiment over philosophical discussions.

c. nonmathematical thinking.

d. None of these.

Science greatly advanced when Galileo favored

a. philosophical discussions over experiment.

b. experiment over philosophical discussions.

c. nonmathematical thinking.

d. None of these.

Galileo said that if you rolled a ball along a level surface it would

a. soon slow down due to its natural tendency to come to rest.

b. keep rolling without slowing if no friction acted upon it.

c. roll as long as its inertia nudged it along.

d. soon roll in the opposite direction.

a. soon slow down due to its natural tendency to come to rest.

b. keep rolling without slowing if no friction acted upon it.

c. roll as long as its inertia nudged it along.

d. soon roll in the opposite direction.

Galileo said that if you rolled a ball along a level surface it would

When Galileo rolled a ball down one incline so that at the bottom it rolled up another, he found that the ball rolled

a. almost to its initial height.

b. halfway to its original height.

c. to its original height.

d. higher than its original height.

When Galileo rolled a ball down one incline so that at the bottom it rolled up another, he found that the ball rolled

a. almost to its initial height.

b. halfway to its original height.

c. to its original height.

d. higher than its original height.

According to Galileo, inertia is a

a. force like any other force.

b. special kind of force.

c. property of all matter.

d. concept opposite to force.

According to Galileo, inertia is a

a. force like any other force.

b. special kind of force.

c. property of all matter.

d. concept opposite to force.

Which of these is NOT a vector quantity?

a. Speed

b. Velocity

c. Force

d. All are vector quantities.

Which of these is NOT a vector quantity?

a. Speed

b. Velocity

c. Force

d. All are vector quantities.

When dishes remain on a table when you yank away a tablecloth, you’re

illustrating

a. friction.

b. inertia.

c. constant motion.

d. F = 0.

When dishes remain on a table when you yank away a tablecloth, you’re

illustrating

a. friction.

b. inertia.

c. constant motion.

d. F = 0.

If gravity between the Sun and Earth suddenly vanished, Earth would

continue moving in

a. a curved path.

b. an outward spiral path.

c. an inward spiral path.

d. a straight-line path.

If gravity between the Sun and Earth suddenly vanished, Earth would

continue moving in

a. a curved path.

b. an outward spiral path.

c. an inward spiral path.

d. a straight-line path.

A space probe in remote outer space continues moving

a. because some kind of force acts on it.

b. in a curved path.

c. even though no force acts on it.

d. due to gravity.

A space probe in remote outer space continues moving

a. because some kind of force acts on it.

b. in a curved path.

c. even though no force acts on it.

d. due to gravity.

Consider a ball resting in the middle of a cart. When you quickly jerk the cart

forward, the ball

a. hits the front of the cart.

b. hits the back of the cart.

c. remains in the middle of the cart.

d. All of these are possible, depending on how quickly the cart is pulled.

Consider a ball resting in the middle of a cart. When you quickly jerk the cart

forward, the ball

a. hits the front of the cart.

b. hits the back of the cart.

c. remains in the middle of the cart.

d. All of these are possible, depending on how quickly the cart is pulled.

Explanation: The ball tends to remain at rest, and the back of the cart intercepts it, so the back of the cart and the ball hit each other.

A girl pushes a cart to the left with a 100-N force. A boy pushes it to the right with a 50-N force. The

net force exerted by the girl and the boy is

a. 100 N to the left.

b. 100 N to the right.

c. 50 N to the left.

d. 50 N to the right.

a. 100 N to the left.

b. 100 N to the right.

c. 50 N to the left.

d. 50 N to the right.

A girl pushes a cart to the left with a 100-N force. A boy pushes it to the right with a 50-N force. The

net force exerted by the girl and the boy is

When a 10-kg block is simultaneously pushed eastward with a force of 20 N and westward with

15 N, the combination of these forces on the block is

a. 35 N west.

b. 35 N east.

c. 5 N east.

d. 5 N west.

When a 10-kg block is simultaneously pushed eastward with a force of 20 N and westward with

15 N, the combination of these forces on the block is

a. 35 N west.

b. 35 N east.

c. 5 N east.

d. 5 N west.

When a 10-N object is suspended at rest by two vertical strands of rope, the

tension in each rope is

a. slightly less than 5 N.

b. 5 N.

c. slightly more than 5 N.

d. 10 N.

When a 10-N object is suspended at rest by two vertical strands of rope, the

tension in each rope is

a. slightly less than 5 N.

b. 5 N.

c. slightly more than 5 N.

d. 10 N.

When sign painters Burl and Paul stand on opposite ends of a scaffold, the

tensions in the two supporting ropes

a. are equal.

b. depend on the relative weights of Burl and Paul.

c. combine to equal zero.

d. are in equilibrium.

a. are equal.

b. depend on the relative weights of Burl and Paul.

c. combine to equal zero.

d. are in equilibrium.

Explanation: If they have equal weights, then tensions in both ropes would be the same. If Burl is heavier than Paul, then more weight is supported by Burl’s rope and tension in it is greater.

When sign painters Burl and Paul stand on opposite ends of a scaffold, the

tensions in the two supporting ropes

If Burl carried Paul piggy-back while standing in the middle of a scaffold, the

tensions in the two supporting ropes would

a. cancel to zero.

b. be equal.

c. be unequal.

d. more easily support Burl and Paul.

If Burl carried Paul piggy-back while standing in the middle of a scaffold, the

tensions in the two supporting ropes would

a. cancel to zero.

b. be equal.

c. be unequal.

d. more easily support Burl and Paul.

Burl and Paul have a total weight of 1300 N. The tensions in the ropes that support the

scaffold they stand on add to 1700 N. The weight of the scaffold itself must be

a. 400 N.

b. 500 N.

c. 600 N.

d. 800 N.

Burl and Paul have a total weight of 1300 N. The tensions in the ropes that support the

scaffold they stand on add to 1700 N. The weight of the scaffold itself must be

a. 400 N.

b. 500 N.

c. 600 N.

d. 800 N.

Place a book that weighs 10 N on a table and the support force on the book is

a. slightly less than 10 N.

b. 10 N.

c. slightly greater than 10 N.

d. dependent on whether the book is flat or stands upright.

Place a book that weighs 10 N on a table and the support force on the book is

a. slightly less than 10 N.

b. 10 N.

c. slightly greater than 10 N.

d. dependent on whether the book is flat or stands upright.

The equilibrium rule, F = 0, applies to

a. objects or systems at rest.

b. objects or systems in uniform motion in a straight line.

c. Both of these.

d. Neither of these.

The equilibrium rule, F = 0, applies to

a. objects or systems at rest.

b. objects or systems in uniform motion in a straight line.

c. Both of these.

d. Neither of these.

The net force on any object in equilibrium is

a. zero.

b. 10 meters per second squared.

c. equal to its weight.

d. somewhat less than its weight.

The net force on any object in equilibrium is

a. zero.

b. 10 meters per second squared.

c. equal to its weight.

d. somewhat less than its weight.

Earth moves about 30 km/s relative to the Sun. When you jump upward in front of a wall, the wall doesn’t slam into you at 30 km/s. This is because

the wall

a. has too little gravity to influence you.

b. moves in an opposite direction to you.

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

d. has negligible inertia compared with the Sun.

Earth moves about 30 km/s relative to the Sun. When you jump upward in front of a wall, the wall doesn’t slam into you at 30 km/s. This is because

the wall

a. has too little gravity to influence you.

b. moves in an opposite direction to you.

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

d. has negligible inertia compared with the Sun.