Conceptual Physics - Chapter 5

One end of a rope is pulled with 100 N, while the opposite end also is pulled with 100 N. The tension in the rope is 50 N. 200 N. 100 N. 0 N.

100 N.

A soccer player kicks a ball with 1500 N of force. The ball exerts a reaction force against the player's foot of somewhat less than 1500 N. 1500 N. somewhat more than 1500 N. None of the above.

1500 N.

Two people, one twice as massive as the other, attempt a tug-of-war with 12 meters of rope on frictionless ice. After a brief time, they meet. The heavier person slides a distance of 3 m. 4 m. 0 m. 6 m.

4 m.

An orange, a wheeled trolley, and an apple are placed inside a dotted rectangle that represents a system. The trolley and the apple are on a horizontal floor. The orange sits at the top of the trolley. The trolley is pulled rightward via a horizontal string by the apple. Two dashed vectors pointing in opposite directions are displayed on the string. One vector points from the apple, to the left, and the other vector points from the orange, to the right., identify the force that accelerates the apple-orange system. A friction force acting on apple's feet. A tension force in the rope between the apple and the orange. A friction force acting on the wheels under orange. No force accelerates the system.

A friction force acting on apple's feet.

Fill in the blanks: Newton's first law is often called the law of ____; Newton's second law is the law of ____; and Newton's third law is the law of ____. Action, inertia, force Inertia, acceleration, action -reaction Inertia, net force, friction Acceleration, inertia, action -reaction

Inertia, acceleration, action -reaction

When you step off a curb, Earth pulls you downward and you pull Earth upward. Why do you not sense Earth moving upward toward you? Earth is fixed, so it cannot move. Earth can move, but other objects on it prevent it from moving. It moves, but by an imperceptible amount. None of the above.

It moves, but by an imperceptible amount.

Can you push on a wall without the wall pushing back on you? No, because your push is part of an interaction with the wall. Yes, you can push on a wall without the wall pushing back on you.

No, because your push is part of an interaction with the wall.

Can you physically touch a person without that person touching you with the same amount of force? No, when you touch a person, they must touch you with an equal and opposite force. Yes, you can touch a person while they choose to not touch you back. Yes, when a heavier person touches a lighter person, the lighter person touches back with less force. Yes, when you touch a person, they touch you back with a force that is slightly less due to friction.

No, when you touch a person, they must touch you with an equal and opposite force.

Because the forces that act on a cannonball and the recoiling cannon from which it is fired are equal in magnitude, why are the accelerations of both so different? The cannon weighs so much that friction with the ground alone prevents it from accelerating. The force from the cannonball on the cannon produces little acceleration because it lasts for such a brief time. The cannon pushes on the cannonball with a much greater force than the cannonball pushes on the cannon. Remember F=ma, and note that the cannon has a much greater mass than the cannonball, so the cannon accelerates less for the same force.

Remember F=ma, and note that the cannon has a much greater mass than the cannonball, so the cannon accelerates less for the same force.

How does the magnitude of acceleration of the rifle compare with the magnitude of acceleration of the bullet, and why? The magnitude of acceleration of the rifle is greater than the magnitude of acceleration of the bullet. Even though they experience the same magnitude of force, the mass of the rifle is greater, and so the rifle will experience a greater acceleration than the bullet. The acceleration of the rifle is smaller than the acceleration of the bullet. They experience the same magnitude of force, but the mass of the rifle is greater, and so the rifle will experience a smaller acceleration than the bullet. The magnitude of acceleration of the rifle is equal to the magnitude of acceleration of the bullet because they experience the same magnitude of force.

The acceleration of the rifle is smaller than the acceleration of the bullet. They experience the same magnitude of force, but the mass of the rifle is greater, and so the rifle will experience a smaller acceleration than the bullet.

How does the distance traveled by the bullet compare with the distance traveled by the rifle in the same time, and why? The bullet will travel the same distance as the rifle because they have equal magnitudes of acceleration. The rifle will travel farther than the bullet because it has a greater magnitude of acceleration. The bullet will travel farther than the rifle because it has a greater magnitude of acceleration.

The bullet will travel farther than the rifle because it has a greater magnitude of acceleration.

How does a helicopter get its lifting force? The helicopter exerts downward forces on air; the reaction forces of the air on the helicopter are upward and called lift. The helicopter exerts a downward force on Earth; the reaction force of Earth on the helicopter is called lift. The helicopter exerts upward forces on the air; the reaction forces of the air on the helicopter are downward and called lift. The helicopter exerts downward forces on the air that are slightly greater than the force of gravity, so it can hover.

The helicopter exerts downward forces on air; the reaction forces of the air on the helicopter are upward and called lift.

How does the force on the rifle compare with the force on the bullet, and why? The magnitude of the force of the rifle is equal to the magnitude of force on the bullet and both forces are in the same direction, because for every action there is an equal reaction. The force on the rifle is greater than the force on the bullet because the mass of the rifle is greater. The force on the rifle is less than the force on the bullet because the mass of the rifle is greater. The magnitude of the force of the rifle is equal to the magnitude of force on the bullet and the forces are in the opposite direction, because for every action there is an equal and opposite reaction.

The magnitude of the force of the rifle is equal to the magnitude of force on the bullet and the forces are in the opposite direction, because for every action there is an equal and opposite reaction.

What happens to the magnitude of the normal vector on a block resting on an incline when the angle of the incline increases? The magnitude is zero. The magnitude of the normal vector decreases. The magnitude of the normal vector remains the same. The magnitude of the normal vector increases.

The magnitude of the normal vector decreases.

A small car and a large truck have a head-on collision. Which of the following statements is true? The greater force acts on the car. The greater force acts on the truck. Both forces are identical. The magnitudes of both forces are the same.

The magnitudes of both forces are the same.

What specific force is accelerating Nellie (Figure 5.23 in the textbook) down the hill? (assume friction to be neglectable) Normal force The y-component of the force of gravity The x-component of the force of gravity Gravity

The x-component of the force of gravity

A small insect hits your windshield while you are driving in the highway. How do you compare the magnitude and direction of the force exerted by the car on the insect versus the force of the insect on the car? They have the same magnitude and opposite directions. They are opposite and the car exerts a higher force on the bug. They are equal and in the same direction. They are equal and perpendicular to each other.

They have the same magnitude and opposite directions.

How many forces are required for an interaction? One force, an action, is needed for an interaction. Two forces, a contact force and a friction force, are needed for an interaction. One force, a reaction, is needed for an interaction. Two forces, an action and a reaction, are needed for an interaction.

Two forces, an action and a reaction, are needed for an interaction.

State two forms of Newton's third law of motion. For every action there is an unequal and opposite reaction. Whenever one object exerts a force on a second object, the second object exerts an unequal and opposite force on the first. Whenever one object exerts a force on a second object, the second object exerts an equal and opposite force on the first. Whenever one object exerts a force on a second object, the second object exerts an unequal and identical force on the first. For every action there is an equal and opposite reaction. For every action there is an identical reaction. Whenever one object exerts a force on a second object, the second object exerts an equal and identical force on the first. For every action there is an opposite reaction.

Whenever one object exerts a force on a second object, the second object exerts an equal and opposite force on the first. For every action there is an equal and opposite reaction.

To produce a net force on a system, must there be an externally applied net force? No, an internal net force is sufficient. Yes, there must be an external net force on the system. Yes. To accelerate, the internal reaction forces must be zero. No. To accelerate, the internal action forces must not equal the internal reaction forces.

Yes, there must be an external net force on the system.

Earth pulls down on you with a gravitational force that you call your weight. Do you pull up on Earth with the same amount of force? No, the contact force from the ground cancels the force by you on Earth. Yes, you pull up on Earth with the same force. No, the contact force from the ground cancels the force of Earth on you. Earth exerts a much greater force on you than you exert on Earth.

Yes, you pull up on Earth with the same force.

Force vector components for a sled pulled horizontally by a rope at an upward angle _______. are normally at right angles to each other add up to 180° are always opposite each other add up to 90°

are normally at right angles to each other

The team to win in a tug-of-war is the team that _______. pushes harder on the floor while holding the rope has the greatest self confidence pulls with the greater force yanks the rope

pushes harder on the floor while holding the rope

The force that propels a rocket is that provided by _______. energetic reactions as the fuel is burned the expelled gas pushing on the rocket ejected fuel decreased mass

the expelled gas pushing on the rocket

A boxer cannot exert much force on a piece of tissue paper suspended in air because _______. the time of the interaction is too brief there is little follow-through with the punch the tissue lacks enough strength the tissue paper has too little mass to exert much force on the boxer's fist

the tissue paper has too little mass to exert much force on the boxer's fist

Earth pulls on the moon. Similarly, the moon pulls on Earth, evidence that these two pulls comprise an action-reaction pair. the moon is smaller so its pull is smaller. Earth is larger so its pull is larger. larger objects pull harder.

these two pulls comprise an action-reaction pair.