# Newton’s law of motions sample questions

The following questions and problems are from “Physics 7th edition by Cutnell and Johnson, Chapter 4” which includes the concepts like Newton’s laws of motion, the vector nature of Newton’s second law of motion, type of forces (gravitational, normal, static and kinetic/frictional forces, tension force), equilibrium and non-equilibrium applications of Newton’s laws of motion.

Please consider significant figures and if possible, draw visual graphics.

Conceptual Questions:

1. Why do you lunge forward when your car suddenly comes to a halt? Why are you pressed backward against the seat when your car rapidly accelerates? In your explanation, refer to the most appropriate one of Newton’s three laws of motion.

2. The net external force acting on an object is zero. It is possible for the object to be traveling with a velocity that is not zero? If your answer is yes, state whether any conditions must be placed on the magnitude and direction of the velocity. If your answer is no, provide the reason for your answer.

3. Is a net force being applied to an object when the object is moving downward (a) with a constant acceleration of 9.80 m/s^2 and (b) with a constant velocity of 9.80 m/s? Explain.

4. A father and his seven year old daughter are facing each other on the ice skates. With their hands, they push off against one another.
(a) Compare the magnitudes of the pushing forces that they experience.
(b) Which one, if either, experiences the larger acceleration? Account for your answer.

5. According to Newton’s third law, when you push on an object, the object pushes you back on you with an oppositely directed force of equal magnitude. If the object is a massive crate resting on the floor, it would probably not move. Some people think that the reason the crate does not move is that the two oppositely directed pushing forces cancel. Explain why this logic is faulty and why the crate does not move.

6. When a body is moved from the sea level to the top of the mountain, what changes – the body’s mass, its weight, or both? Explain.

7. The force of air resistance acts to oppose the motion of an object moving through the air. A ball is thrown upward and eventually returns to the ground.
(a) As the ball moves upward, is the net force that acts on the ball greater than, less than, or equal to its weight? Justify your answer.
(b) Repeat part (a) for the downward motion of the ball.

8. A person has a choice of either pushing or pulling a sled at a constant velocity. Friction is present. If the angle θ is the same in both cases, does it require less force to push or to pull? Account your answer.

9. Suppose that the coefficients of static and kinetic friction have values such that µs = 1.4 µk for a crate in contact with a cement floor. Does this mean that the magnitude of the static frictional force acting on the crate at rest would always be 1.4 times the magnitude of the kinetic frictional force acting on the moving crate? Give your reasoning.

10. Can an object ever be in equilibrium if the object is acted on by only (a) a single nonzero force, (b) two forces that point in mutually perpendicular directions, and (c) two forces that point in directions that are not perpendicular? Account for your answer.

11. During the final stages of descent, a sky diver with an open parachute approaches the ground with a constant velocity. The wind does not blow him from side to side. Is the sky diver in equilibrium and, if so, what forces are responsible for the equilibrium?

12. A weight hangs from a ring at the middle of a rope. Can the person who is pulling on the right end of the rope ever make the rope perfectly horizontal? Explain your answer in terms of the forces that act on the ring.

Problems:

(Newton’s Law of Motion)

1. A boat has a mass of 6800 kg. Its engines generate a drive force of 4100 N, due west, while the wind exerts a force of 800 N, due east, and the water exerts a resistive force of 1200 N due east. What is the magnitude and direction of the boat’s acceleration?

2. A 15-g bullet is fired from a rifle. It takes 2.50 x 10^-3 s for the bullet to travel the length of the barrel with a speed of 715 m/s. assuming that the acceleration of the bullet is constant, find the average net force exerted on the bullet.

(The Vector Nature of Newton’s Second Law of Motion and Newton’s Third Law):

3. A 350-kg sailboat has an acceleration of 0.62 m/s^2 at an angle of 64 degrees north of east. Find the magnitude and the direction of the net force that acts on the sailboat.

4. When a parachute opens, the air exerts a large drag force on it. This upward force is initially greater than the weight of the sky diver and, thus, slows him down. Suppose the weight of the sky diver is 915 N and the drag force has a magnitude of 1027 N. The mass of the sky diver is 93.4 kg. What are the magnitude and direction of his acceleration?

(Gravitational Force)

5. A rock of mass 45 kg accidentally breaks loose from the edge of a cliff and falls straight down. The magnitude of the air resistance that opposes its downward motion is 18 N. What is the magnitude of the acceleration of the rock?

6. Synchronous communications satellites are placed in a circular orbit that is 3.59 x 10^7 m above the surface of the earth. What is the magnitude of the acceleration due to gravity at this distance?

7. Mars has a mass of 6.46 x 10^23 kg and a radius of 3.39 x 10^6 m.
(a) What is the acceleration due to gravity on Mars?
(b) How much would a 65kg person weigh on this planet?

(The Normal Force, Static and kinetic frictional Force)

8. A block whose weight is 45.0 N rests on a horizontal table. A horizontal force of 36.0 N is applied to the block. The coefficients of static and kinetic friction are 0.650 and 0.420, respectively. Will the block move under the influence of the force, and if so, what will be the block’s acceleration? Explain your reasoning.

9. A 60.0 kg crate rests on a level floor at a shipping dock. The coefficients of static and kinetic friction are 0.760 and 0.410, respectively. What horizontal pushing force is required to (a) just start the crate moving and (b) slide the crate across the dock at a constant speed?

(The tension Force, Equilibrium Applications of Newton’s Law of Motion)

10. A stuntman is being pulled along a rough road at a constant velocity by a cable attached to a moving truck. The cable is parallel to the ground. The mass of the stuntman is 109 kg, and the coefficient of kinetic friction between the road and him is 0.870. Find the tension in the cable.

11. A 1.40-kg bottle of vintage wine is lying horizontally in the rack. The two surfaces on which the bottle rests are 90.0 degrees apart, and the right surface makes an angle of 45.0 degrees with respect to the ground. Each surface exerts a force on the bottle that is perpendicular to the surface. What is the magnitude of each of these forces?

(Non-equilibrium Applications of Newton’s Law of Motion)

12. The two blocks are connected via a pulley. The weight of the block on the table is 422 N and that of the hanging block is 185 N. Ignoring the frictional effects and assuming the pulley to be massless, find (a) the acceleration of the two blocks and (b) the tension of the cord

Get quick assignments help now

## Order NOW to get 15% Discount!

Pages
{{total || ""}}

Why Choose Us

Top Quality and Well-Researched Papers

Keeping in mind your instructions and guidelines, our writers ensure to do extensive research before beginning to write. Unique and quality paper is our top priority.

Our team of writers and editors have many years of experience in academic writing. They are native English speakers and able to handle any academic task with ease.

Free Unlimited Revisions

We offer free unlimited revision to our clients. Whenever you feel the need to revise your work submit to our able editors. Our editors will ensure that your paper will be revised to meet your guidelines.

Prompt Delivery and 100% Money-Back-Guarantee

As a team we work hard to ensure a timely delivery of your papers. All you need to do is specify the time frame that you want you paper be submitted. We will work round the clock to beat the deadline.

Original & Confidential

We value your confidentiality and all our payment method are secure. We also use high end writing tools to ensure that all papers delivered are unique.

Our customer support team are available 24/7 to accept your orders and queries. We are committed to provide you with the best customer experience.

What Our Paper Writing Service Guarantees

You do not have to worry on what to expect because at mypaperwriterspro.com we guarantee you;

Our team of writers and editors is composed of people with diverse writing experiences. All of them have a Ph.D. They are all Ph.D. or M.A. graduates with extensive experience in academic and essay writing. We offer high-quality, original academic writing at an affordable cost.

Every order is written from scratch. We ensure that your papers conform to English conventions and the requirements of your discipline. To ensure originality, we also perform originality checks on all academic papers. Our success rate is 99% and many of our clients achieves their desired grades.

## Zero-plagiarism policy

Mypaperwriterspro has a strict anti-plagiarism policy. To ensure that your paper is not flagged as plagiarism, we take extra precautions when writing it. Professional plagiarism detection software is used by our custom paper experts.

Mypaperwriterspro takes the privacy of clients' information very seriously. Mypaperwriterspro does not disclose any information about our transactions with third-party services. Nobody will ever know that you have hired our paper writing service to help with your paper.

Our website offers online security for our customers. Your passwords and personal information are protected and cannot be accessed by anyone else. Our customers are assured that their accounts will not be compromised by hackers. Learn more about the data that we store and how it is used in our privacy statement.

## Free revision

When you order our paper service, you get unlimited free revisions and unlimited drafts. We will ensure that you submit flawless papers. Our paper help website allows you to request multiple revisions.

If the order form indicates that modifications or adjustments are required, only those should be made. These guidelines include, but are not limited to:

• Revision instructions should not conflict with your original instructions.
• You can request a modification before the purchase is approved. However, there is a 14-day grace period in which you can do this.

You can reach us by email, phone, and live chat. We are always interested in hearing from our customers. We welcome any feedback regarding our paper assistance service. Our customer service representatives are available 24/7, even on holidays and weekends. They can help you place orders, check the status of your order, answer questions, or simply provide information.

Chat with your paper specialist via our live chat. Our professionals are available for unlimited chats. All your questions will be answered within minutes

## Money-back guarantee

Do you still feel dissatisfied with your final paper? Don't worry. Mypaperwriterspro is committed to customer satisfaction.

Although it is rare, you can request a partial or full refund if your final paper is not written to your satisfaction. Mypaperwriterspro views our money-back guarantee more as a right than a benefit.

We believe that our clients deserve the best paper services available online. We offer a simple and straightforward refund process if you are not satisfied with the paper.

You can now contact our live agent via Whatsapp via +1(954) 751-1024
You will get free custom written paper ready for submission to your Blackboard