Chapter 2 Newton’s Laws of Motion – Flashcards

It is important to know that the term inertia refers to

If gravity between the Sun and Earth suddenly vanished, Earth would continue moving in a(n)

Is inertia a property of matter or a force of some kind?

State the law of inertia.

What concept was missing from people's minds in the 16th century when they couldn't believe Earth was moving?

When a bird lets go of a branch and drops to the ground below, why doesn't the moving Earth sweep away from the dropping bird?

What kind of path would the planets follow if suddenly their attraction to the Sun no longer existed?

Which object provides an inertial frame of reference?

You are conducting an experiment inside an elevator that can move in a vertical shaft. A load is hung vertically from the ceiling on a string, and is stationary with respect to you. The tension in the string is measured to be 10% less than the force due to gravity on the load. No other forces are acting on the load. Which of the following statements about the elevator are correct?

You are conducting an experiment inside an elevator that can move in a vertical shaft. A load is hung vertically from the ceiling on a string. The tension in the string is measured to be exactly equal to the force due to gravity on the load. No other forces are acting on the load. Which of the following statements about the elevator are correct?

You are conducting an experiment inside a train car that may move along level rail tracks. A load is hung from the ceiling on a string. The load is not swinging, and the string is observed to make a constant angle of 45 ∘ with the horizontal. No forces other than tension and gravity are acting on the load. Which of the following statements are correct?

Consider the train car described in the previous part. Another experiment is conducted in it: A net force of 20N is applied to an object of mass 5kg . Can you determine the acceleration of the object with respect to the train, and, if so, what is its value?

A 1000-kg car is moving along a straight road down a 30 ∘ slope at a constant speed of 20.0m/s . What is the net force acting on the car?

Consider two cars moving along the same straight road in opposite directions. Car A has a mass of 500kg and has a constant speed of 20m/s ; car B has a mass of 800kg and a constant speed of 15m/s . What can you say about the net forces on the cars?

In an inertial frame of reference, a series of experiments is conducted. In each experiment, two or three forces are applied to an object. The magnitudes of these forces are given. No other forces are acting on the object. In which cases may the object possibly remain at rest? The forces applied are as follows:

In an inertial frame of reference, a series of experiments is conducted. In each experiment, two or three forces are applied to an object. The magnitudes of these forces are given. No other forces are acting on the object. In which cases may the object possibly move at a constant velocity of 256m/s ? The forces applied are as follows:

An object cannot remain at rest unless which of the following holds?

If a block is moving to the left at a constant velocity, what can one conclude?

A block of mass 2kg is acted upon by two forces: 3N (directed to the left) and 4N (directed to the right). What can you say about the block's motion?

A massive block is being pulled along a horizontal frictionless surface by a constant horizontal force. The block must be __________.

Two forces, of magnitude 4N and 10N , are applied to an object. The relative direction of the forces is unknown. The net force acting on the object __________.

Newton's second law of motion links force, acceleration, and _______.

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 _______.

The reason a 20-kg rock falls no faster than a 10-kg rock in free fall is that _______.

A heavy parachutist has a greater terminal speed compared with a lighter parachutist with the same size parachute because the heavier person _______.

State Newton's second law

What is the net force that acts on a 10-N freely falling object?

What is the net force that acts on a 10-N falling object when it encounters 4 N of air resistance? 10 N of air resistance?

Is acceleration directly or inversely proportional to force? Give an example

Is acceleration directly or inversely proportional to mass? Give an example.

If the mass of a sliding block is tripled at the same time that the net force on it is tripled, how does the resulting acceleration compare to the original acceleration?

Why doesn't a heavy object accelerate more than a light object when both are freely falling?

What two principal factors affect the force of air resistance on a falling object?

What is the acceleration of a falling object that has reached its terminal velocity?

If two objects of the same size fall through air at different speeds, which encounters the greater air resistance?

Why does a heavy parachutist fall faster than a lighter parachutist who wears the same size parachute?

Whenever one object exerts a force on a second object, the second object exerts a force on the first that _______.

How hard a boxer's punch lands depends on the _______.

When you push against a wall with your fingers, they bend because they experience a force. Identify this force

A boxer can hit a heavy bag with great force. Why can't he hit a sheet of tissue paper in midair with the same amount of force?

How many forces are required for a single interaction?

In this chapter, we treated force as a push or pull, now we say it is part of an interaction. Is a force a push or pull, or part of an interaction?

The force that directly propels a motor scooter along a highway is that provided by the _______.

In terms of forces, what is necessary to accelerate a system?

How does a helicopter get its lifting force?

To what law of physics do we refer when we say you cannot touch without being touched?

If body A and body B are both within a system, can forces between them affect the acceleration of the system?

State Newton's third law

Consider hitting a baseball with a bat. If we call the force of the bat against the ball the action force, what is the reaction force?

Is it correct to say that action and reaction forces always act on different bodies? Defend your answer

If the force that acts on a cannonball and the force that acts on the recoiling cannon from which it is fired are equal in magnitude, why do the cannonball and the cannon have very different accelerations?

Identify the force that propels a rocket into space.

The auto in the sketch moves forward as the brakes are applied. A bystander says that during the interval of braking, the auto's velocity and acceleration are in opposite directions. Do you agree or disagree?

The primary physics that got humans to the Moon was _______.

Which of Newton's laws focuses on inertia? Which on acceleration? Which on action-reaction?