Transcript Conceptual Physical Science 5e — Chapter 2

Conceptual Physical Science 5e — Chapter 2
Conceptual
Physical
Science
5th Edition
Chapter 2:
Newton’s Laws
of Motion
© 2012 Pearson Education, Inc.
© 2012 Pearson Education, Inc.
Conceptual Physical Science 5e — Chapter 2
The concept of inertia is attributed to
A.
B.
C.
D.
Galileo.
Newton.
Both.
Neither.
© 2012 Pearson Education, Inc.
Conceptual Physical Science 5e — Chapter 2
The concept of inertia is attributed to
A.
B.
C.
D.
Galileo.
Newton.
Both.
Neither.
Comment:
Galileo discovered the concept and Newton elevated it to his first
law of motion.
© 2012 Pearson Education, Inc.
Conceptual Physical Science 5e — Chapter 2
If gravity between the Sun and Earth suddenly vanished,
Earth would move in
A.
B.
C.
D.
a curved path.
a straight-line path.
an outward spiral path.
an inward spiral path.
© 2012 Pearson Education, Inc.
Conceptual Physical Science 5e — Chapter 2
If gravity between the Sun and Earth suddenly vanished,
Earth would move in
A.
B.
C.
D.
a curved path.
a straight-line path.
an outward spiral path.
an inward spiral path.
© 2012 Pearson Education, Inc.
Conceptual Physical Science 5e — Chapter 2
Seat belts and air bags in a car are mostly linked to the
effects of Newton’s
A.
B.
C.
D.
first law.
second law.
third law.
law of gravity.
© 2012 Pearson Education, Inc.
Conceptual Physical Science 5e — Chapter 2
Seat belts and air bags in a car are mostly linked to the
effects of Newton’s
A.
B.
C.
D.
first law.
second law.
third law.
law of gravity.
Comment:
Although Newton’s three laws of motion are at play, the first law is
most applicable.
© 2012 Pearson Education, Inc.
Conceptual Physical Science 5e — Chapter 2
The net force on any object in equilibrium is
A.
B.
C.
D.
zero.
10 meters per second squared.
equal to its weight.
None of the above.
© 2012 Pearson Education, Inc.
Conceptual Physical Science 5e — Chapter 2
The net force on any object in equilibrium is
A.
B.
C.
D.
zero.
10 meters per second squared.
equal to its weight.
None of the above.
© 2012 Pearson Education, Inc.
Conceptual Physical Science 5e — Chapter 2
When standing in the aisle of a smoothly riding bus, you
drop a coin from above your head. The falling coin will land
A.
B.
C.
D.
at your feet.
slightly in front of your feet.
slightly in back of your feet.
at a location not listed above.
© 2012 Pearson Education, Inc.
Conceptual Physical Science 5e — Chapter 2
When standing in the aisle of a smoothly riding bus, you
drop a coin from above your head. The falling coin will land
A.
B.
C.
D.
at your feet.
slightly in front of your feet.
slightly in back of your feet.
at a location not listed above.
Explanation:
The horizontal velocity of the coin remains the same as it falls.
© 2012 Pearson Education, Inc.
Conceptual Physical Science 5e — Chapter 2
Consider a cart with a ball resting in its middle. When you
quickly jerk the cart forward, the
A.
B.
C.
D.
front of the cart hits the ball.
back of the cart hits the ball.
ball remains in the middle as the cart moves forward.
above can all occur depending on how quickly the cart is pulled.
© 2012 Pearson Education, Inc.
Conceptual Physical Science 5e — Chapter 2
Consider a cart with a ball resting in its middle. When you
quickly jerk the cart forward, the
A.
B.
C.
D.
front of the cart hits the ball.
back of the cart hits the ball.
ball remains in the middle as the cart moves forward.
above can all occur depending on how quickly the cart is pulled.
Explanation:
Relative to the ground, the ball tends to remain at rest while the
cart moves beneath it. Hence, the back of the cart hits the ball.
© 2012 Pearson Education, Inc.
Conceptual Physical Science 5e — Chapter 2
When a 10-kg block is simultaneously pushed eastward
with 20 N and westward with 15 N, the net force on the
block is
A.
B.
C.
D.
35 N west.
35 N east.
5 N west.
5 N east.
© 2012 Pearson Education, Inc.
Conceptual Physical Science 5e — Chapter 2
When a 10-kg block is simultaneously pushed eastward
with 20 N and westward with 15 N, the net force on the
block is
A.
B.
C.
D.
35 N west.
35 N east.
5 N west.
5 N east.
© 2012 Pearson Education, Inc.
Conceptual Physical Science 5e — Chapter 2
When a 10-kg block is simultaneously pushed eastward
with 20 N and westward with 15 N, the acceleration of the
block is
A.
B.
C.
D.
0.5 m/s2 east.
0.5 m/s2 west.
0.5 m/s2 east–west.
None of the above.
© 2012 Pearson Education, Inc.
Conceptual Physical Science 5e — Chapter 2
When a 10-kg block is simultaneously pushed eastward
with 20 N and westward with 15 N, the acceleration of the
block is
A.
B.
C.
D.
0.5 m/s2 east.
0.5 m/s2 west.
0.5 m/s2 east–west.
None of the above.
Explanation:
Note the mass of a 10-N block is about 1 kg. Then
a = F/m = (20 N – 15 N)/1 kg = 0.5 m/s2.
© 2012 Pearson Education, Inc.
Conceptual Physical Science 5e — Chapter 2
The connection between mass, acceleration, and force is
embodied in Newton’s
A.
B.
C.
D.
first law.
second law.
third law.
law of gravity.
© 2012 Pearson Education, Inc.
Conceptual Physical Science 5e — Chapter 2
The connection between mass, acceleration, and force is
embodied in Newton’s
A.
B.
C.
D.
first law.
second law.
third law.
law of gravity.
Comment:
acceleration = force/mass.
© 2012 Pearson Education, Inc.
Conceptual Physical Science 5e — Chapter 2
A cart is pushed and undergoes a certain acceleration.
Consider how the acceleration would compare if it were
pushed with twice the net force while its mass increased by
four. Then its acceleration would be
A.
B.
C.
D.
one quarter.
the same.
twice.
None of the above.
© 2012 Pearson Education, Inc.
Conceptual Physical Science 5e — Chapter 2
A cart is pushed and undergoes a certain acceleration.
Consider how the acceleration would compare if it were
pushed with twice the net force while its mass increased by
four. Then its acceleration would be
A.
B.
C.
D.
one quarter.
the same.
twice.
None of the above.
Explanation:
Twice the force acting on four times the mass gives half the
acceleration. So the acceleration would be half—none of the
above.
© 2012 Pearson Education, Inc.
Conceptual Physical Science 5e — Chapter 2
A 100-kg vehicle accelerates at 1 m/s2 when the net force
on it is
A.
B.
C.
D.
1 N.
10 N.
100 N.
1000 N.
© 2012 Pearson Education, Inc.
Conceptual Physical Science 5e — Chapter 2
A 100-kg vehicle accelerates at 1 m/s2 when the net force
on it is
A.
B.
C.
D.
1 N.
10 N.
100 N.
1000 N.
Explanation:
From a = F/m, simple rearrangement gives:
F = ma = (100 kg)(1 m/s2) = 100 N.
© 2012 Pearson Education, Inc.
Conceptual Physical Science 5e — Chapter 2
A car pulling a trailer accelerates when the gas pedal is
pushed to the floor. If the trailer becomes disconnected, the
acceleration of the car will
A.
B.
C.
D.
decrease.
increase.
remain the same.
None of the above.
© 2012 Pearson Education, Inc.
Conceptual Physical Science 5e — Chapter 2
A car pulling a trailer accelerates when the gas pedal is
pushed to the floor. If the trailer becomes disconnected, the
acceleration of the car will
A.
B.
C.
D.
decrease.
increase.
remain the same.
None of the above.
Comment:
Newton’s second law tells us that if the mass of something
decreases while the force remains the same, then the
acceleration will increase.The car minus the trailer has less mass.
© 2012 Pearson Education, Inc.
Conceptual Physical Science 5e — Chapter 2
When you toss a rock straight upward, which is no longer
present at the top of its path?
A.
B.
C.
D.
Mass.
Speed.
Acceleration.
All of the above.
© 2012 Pearson Education, Inc.
Conceptual Physical Science 5e — Chapter 2
When you toss a rock straight upward, which is no longer
present at the top of its path?
A.
B.
C.
D.
Mass.
Speed.
Acceleration.
All of the above.
Explanation:
It still has a force on it, mg, so a = F/m = mg/m = g. Only speed is
zero at the top.
© 2012 Pearson Education, Inc.
Conceptual Physical Science 5e — Chapter 2
A falling object that reaches terminal velocity continues to
have
A.
B.
C.
D.
speed.
a nonzero net force.
acceleration.
All of the above.
© 2012 Pearson Education, Inc.
Conceptual Physical Science 5e — Chapter 2
A falling object that reaches terminal velocity continues to
have
A.
B.
C.
D.
speed.
a nonzero net force.
acceleration.
All of the above.
Explanation:
At terminal velocity, both net force and acceleration are zero.
© 2012 Pearson Education, Inc.
Conceptual Physical Science 5e — Chapter 2
A heavy parachutist has a greater terminal speed
compared with a light parachutist with the same size chute,
because the heavier person
A.
B.
C.
D.
has to fall faster for air resistance to match his weight.
is more greatly attracted by gravity to the ground below.
has a greater air resistance.
has none of the above.
© 2012 Pearson Education, Inc.
Conceptual Physical Science 5e — Chapter 2
A heavy parachutist has a greater terminal speed
compared with a light parachutist with the same size chute,
because the heavier person
A.
B.
C.
D.
has to fall faster for air resistance to match his weight.
is more greatly attracted by gravity to the ground below.
has a greater air resistance.
has none of the above.
Explanation:
At terminal speed, both weight and air resistance have the same
magnitude. To get that greater magnitude of air resistance, falling
speed has to be greater for the heavier person.
© 2012 Pearson Education, Inc.
Conceptual Physical Science 5e — Chapter 2
When a 10-kg falling object encounters 10 N of air
resistance, its acceleration is
A.
B.
C.
D.
less than g.
g.
more than g.
unknown—there is not enough information.
© 2012 Pearson Education, Inc.
Conceptual Physical Science 5e — Chapter 2
When a 10-kg falling object encounters 10 N of air
resistance, its acceleration is
A.
B.
C.
D.
less than g.
g.
more than g.
unknown—there is not enough information.
Explanation:
Any object that encounters air resistance accelerates at less than
g.
© 2012 Pearson Education, Inc.
Conceptual Physical Science 5e — Chapter 2
A soccer ball is kicked to a 30-m/s speed. While being
kicked, the amount of force of the player’s foot on the ball is
A.
B.
C.
D.
less than the amount of force on the foot.
the same as the amount of force on the foot.
more than the amount of force on the foot.
None of the above.
© 2012 Pearson Education, Inc.
Conceptual Physical Science 5e — Chapter 2
A soccer ball is kicked to a 30-m/s speed. While being
kicked, the amount of force of the player’s foot on the ball is
A.
B.
C.
D.
less than the amount of force on the foot.
the same as the amount of force on the foot.
more than the amount of force on the foot.
None of the above.
Explanation:
Newton’s third law, pure and simple. The speed of the ball is
irrelevant. The amount of force on the ball and on the foot is the
same.
© 2012 Pearson Education, Inc.
Conceptual Physical Science 5e — Chapter 2
A karate chop delivers a blow of 3500 N to a board that
breaks. The force that acts on the hand during this event is
A.
B.
C.
D.
less than 3500 N.
3500 N.
greater than 3500 N.
None of the above.
© 2012 Pearson Education, Inc.
Conceptual Physical Science 5e — Chapter 2
A karate chop delivers a blow of 3500 N to a board that
breaks. The force that acts on the hand during this event is
A.
B.
C.
D.
less than 3500 N.
3500 N.
greater than 3500 N.
None of the above.
Comment:
Hence, the need for a strong hand!
© 2012 Pearson Education, Inc.
Conceptual Physical Science 5e — Chapter 2
Earth pulls on the Moon. Similarly, the Moon pulls on Earth,
evidence that
A.
B.
C.
D.
Earth and Moon are pulling on each other.
Earth’s and Moon’s pulls comprise an action–reaction pair of
forces.
Both of the above occur.
None of the above occur.
© 2012 Pearson Education, Inc.
Conceptual Physical Science 5e — Chapter 2
Earth pulls on the Moon. Similarly, the Moon pulls on Earth,
evidence that
A.
B.
C.
D.
Earth and Moon are pulling on each other.
Earth’s and Moon’s pulls comprise an action–reaction pair of
forces.
Both of the above occur.
None of the above occur.
© 2012 Pearson Education, Inc.
Conceptual Physical Science 5e — Chapter 2
The amount of air resistance on a 0.8-N flying squirrel for
terminal speed is
A.
B.
C.
D.
less than 0.8 N.
0.8 N.
more than 0.8 N.
Depends on the orientation of its body.
© 2012 Pearson Education, Inc.
Conceptual Physical Science 5e — Chapter 2
The amount of air resistance on a 0.8-N flying squirrel for
terminal speed is
A.
B.
C.
D.
less than 0.8 N.
0.8 N.
more than 0.8 N.
Depends on the orientation of its body.
Explanation:
For terminal speed, net force must equal zero, no matter what the
orientation of the squirrel’s body. How great the terminal speed is
does depend on body orientation. But that’s not the question
asked.
© 2012 Pearson Education, Inc.
Conceptual Physical Science 5e — Chapter 2
As a flying squirrel falls faster and faster through the air,
A.
B.
C.
D.
air resistance increases.
net force decreases.
acceleration decreases.
All of the above.
© 2012 Pearson Education, Inc.
Conceptual Physical Science 5e — Chapter 2
As a flying squirrel falls faster and faster through the air,
A.
B.
C.
D.
air resistance increases.
net force decreases.
acceleration decreases.
All of the above.
© 2012 Pearson Education, Inc.
Conceptual Physical Science 5e — Chapter 2
A tennis ball and a bowling ball are simultaneously
released from rest at the top of your school building. The
ball to reach the ground first will be the
A.
B.
C.
D.
tennis ball.
bowling ball.
Both will hit at the same time.
Any of the above, depending on wind conditions.
© 2012 Pearson Education, Inc.
Conceptual Physical Science 5e — Chapter 2
A tennis ball and a bowling ball are simultaneously
released from rest at the top of your school building. The
ball to reach the ground first will be the
A.
B.
C.
D.
tennis ball.
bowling ball.
Both will hit at the same time.
Any of the above, depending on wind conditions.
Explanation:
Air resistance (not negligible in this case) will act on both when
they fall. But the amount of air resistance on the heavy bowling
ball will be small compared with the ball’s weight. It will therefore
better plow through the air and hit first.
© 2012 Pearson Education, Inc.
Conceptual Physical Science 5e — Chapter 2
How hard a boxer’s punch lands depends on the
A.
B.
C.
D.
mass of what’s being hit.
physical condition of the boxer.
boxer’s attitude.
None of the above.
© 2012 Pearson Education, Inc.
Conceptual Physical Science 5e — Chapter 2
How hard a boxer’s punch lands depends on the
A.
B.
C.
D.
mass of what’s being hit.
physical condition of the boxer.
boxer’s attitude.
None of the above.
Explanation:
Attitude is said to be everything, and physical condition is
important, but not as answers to this question.
© 2012 Pearson Education, Inc.
Conceptual Physical Science 5e — Chapter 2
The force that directly propels a motor scooter along a
highway is that provided by the
A.
B.
C.
D.
engine.
fuel.
tires.
road.
© 2012 Pearson Education, Inc.
Conceptual Physical Science 5e — Chapter 2
The force that directly propels a motor scooter along a
highway is that provided by the
A.
B.
C.
D.
engine.
fuel.
tires.
road.
Explanation:
The tires push back on the road, and in so doing, the road pushes
forward on the tires. It is this force that is directly responsible for
the scooter’s motion. Cheers for Newton’s third law!
© 2012 Pearson Education, Inc.
Conceptual Physical Science 5e — Chapter 2
When you jump vertically upward, strictly speaking, you
cause Earth to
A.
B.
C.
D.
move downward.
also move upward with you.
remain stationary.
move sideways a bit.
© 2012 Pearson Education, Inc.
Conceptual Physical Science 5e — Chapter 2
When you jump vertically upward, strictly speaking, you
cause Earth to
A.
B.
C.
D.
move downward.
also move upward with you.
remain stationary.
move sideways a bit.
Explanation:
When you jump upward, you push downward on Earth. Strictly
speaking, it therefore moves downward. By how much? Not
much, in fact negligibly, because its mass is so much greater than
yours.
© 2012 Pearson Education, Inc.
Conceptual Physical Science 5e — Chapter 2
The force that propels a rocket is provided by
A.
B.
C.
D.
gravity.
its exhaust gases.
Newton’s laws of motion.
the atmosphere against which the rocket pushes.
© 2012 Pearson Education, Inc.
Conceptual Physical Science 5e — Chapter 2
The force that propels a rocket is provided by
A.
B.
C.
D.
gravity.
its exhaust gases.
Newton’s laws of motion.
the atmosphere against which the rocket pushes.
Explanation:
Newton’s laws are at play in rocket propulsion, but the actual
force propelling the rocket is its exhaust gases. As Newton’s third
law tells us, if the rocket pushes exhaust gases downward, the
gases push the rocket upward.
© 2012 Pearson Education, Inc.
Conceptual Physical Science 5e — Chapter 2
Anthony is late for class and is soon reprimanded. Causes
lead to consequences. We can show, however, that this is
not an example of Newton’s third law because
A.
B.
C.
D.
action and supposed reaction are not simultaneous.
the laws of physics apply to inanimate situations, not real-life
ones.
Both of the above are true.
Neither of the above is true.
© 2012 Pearson Education, Inc.
Conceptual Physical Science 5e — Chapter 2
Anthony is late for class and is soon reprimanded. Causes
lead to consequences. We can show, however, that this is
not an example of Newton’s third law because
A.
B.
C.
D.
action and supposed reaction are not simultaneous.
the laws of physics apply to inanimate situations, not real-life
ones.
Both of the above are true.
Neither of the above is true.
Explanation:
Answer B is erroneous, for Newton’s laws govern both inanimate
and animate things. An action–reaction pairing is by definition
simultaneous.
© 2012 Pearson Education, Inc.
Conceptual Physical Science 5e — Chapter 2
Arnold Strongman and little Nellie Newton have a tug-ofwar. The greatest force on the rope is provided by
A.
B.
C.
D.
Arnold, of course.
Nellie, surprisingly.
Both the same, interestingly enough.
None of the above.
© 2012 Pearson Education, Inc.
Conceptual Physical Science 5e — Chapter 2
Arnold Strongman and little Nellie Newton have a tug-ofwar. The greatest force on the rope is provided by
A.
B.
C.
D.
Arnold, of course.
Nellie, surprisingly.
Both the same, interestingly enough.
None of the above.
Comment:
The winner of a tug-of-war is the one who pushes harder against
the ground!
© 2012 Pearson Education, Inc.
Conceptual Physical Science 5e — Chapter 2
A grasshopper has a head-on collision with a speeding
Mack truck. The greatest force acts on the
A.
B.
C.
D.
bug.
truck.
Same amount on each.
Not enough information to say.
© 2012 Pearson Education, Inc.
Conceptual Physical Science 5e — Chapter 2
A grasshopper has a head-on collision with a speeding
Mack truck. The greatest force acts on the
A.
B.
C.
D.
bug.
truck.
Same amount on each.
Not enough information to say.
Comment:
Although the forces are equal in magnitude, the effects of these
forces are drastically different. Don’t confuse something with the
effects of that something.
© 2012 Pearson Education, Inc.
Conceptual Physical Science 5e — Chapter 2
The laws of physics that were employed to get humans to
the Moon are
A.
B.
C.
D.
Newton’s laws of motion.
special relativity.
general relativity.
All of the above.
© 2012 Pearson Education, Inc.
Conceptual Physical Science 5e — Chapter 2
The laws of physics that were employed to get humans to
the Moon are
A.
B.
C.
D.
Newton’s laws of motion.
special relativity.
general relativity.
All of the above.
Explanation:
As the concluding paragraph of Chapter 2 states, Newton’s laws
were and are sufficient for getting humans to the Moon!
© 2012 Pearson Education, Inc.