A circus cannon fires an acrobatic dog, Astro, of mass \(m\), into a net. The speed of Astro as he leaves the cannon is \(v\). A cat, Beta, of mass \(0.5 \mathrm{~m}\) is then fired from the cannon. Assuming that the force exerted on each is constant throughout the cannon barrel, what is the speed of Beta as she leaves the mouth of the cannon? (A) \(2 v\) (B) \(\sqrt{2} v\) (C) \(v\) (D) \(v / \sqrt{2}\) (E) \(v / 2\)

Short Answer

Expert verified
Answer: (A) \(2v\)

Step by step solution

01

Write the impulse experienced by the dog and cat

Impulse experienced by both Astro and Beta = Force x Time Let the impulse experienced by Astro and Beta be denoted as I.
02

Write the change in momentum of Astro and relate it to the impulse

Change in momentum of Astro = mass of Astro (m) x change in velocity of Astro (v) Since Impulse = Change in momentum, I = mv Given that the speed of Astro when he leaves the cannon is \(v\).
03

Write the change in momentum of Beta and relate it to the impulse

Change in momentum of Beta = mass of Beta (0.5m) x change in velocity of Beta (v_beta) Since Impulse = Change in momentum, I = 0.5m * v_beta
04

Set the impulse experienced by Astro and Beta equal and solve for v_beta

Since both Astro and Beta experienced the same impulse: mv = 0.5m * v_beta Now, we can solve for v_beta: v_beta = 2 * v Therefore, the speed of Beta as she leaves the mouth of the cannon is (A) \(2v\).

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Over 30 million students worldwide already upgrade their learning with Vaia!

Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Physics SAT Prep
Understanding the impulse-momentum theorem is crucial for success on the Physics SAT subject test. This theorem connects the concepts of force, time, and changes in momentum, which are frequent topics covered in the exam. When preparing for the SAT, you should become comfortable with calculating the impulse given to an object, as well as interpreting situations involving variable forces.

For example, consider an acrobatic dog being fired from a circus cannon. To solve for the speed of another object fired from the same cannon, such as a cat named Beta in our exercise, you must understand that the impulse provided by the cannon to both the dog and cat is the same. This knowledge directly leads to the conclusion that the speeds at which they are launched are inversely proportional to their masses, given that they receive the same impulse.

When reviewing for the SAT, remember to practice with diverse physics problems to enhance your problem-solving skills and improve your score. Aim for efficiency by understanding the relationships between physical quantities instead of simply memorizing equations.
AP Physics Review
The AP Physics exams test students' understanding of the fundamental concepts of physics and their ability to apply these principles to solve complex problems. The momentum conservation principle is often tested on AP Physics exams, be it in the context of collisions or isolated systems.

For a holistic review, students should hone their skills in problems that require the application of the momentum conservation principle alongside other physics laws and concepts. As an example, the exercise solution illustrates applications of the impulse-momentum theorem and momentum conservation. It demonstrates how the momentum of the acrobatic dog and cat from the circus cannon is conserved due to the constant impulse applied to each.

Deepening your understanding of how to apply the conservation principles in various contexts, such as the one in our exercise, will serve you well in tackling the AP Physics questions. Remember to approach these questions conceptually and use logical reasoning to derive solutions from the principles you've learned.
Momentum Conservation
Momentum conservation is a foundational principle in physics and states that in a closed system with no external net forces, the total momentum remains constant over time. This principle applies to various phenomena, from elastic collisions to rocket propulsion.

The circus cannon scenario in our exercise can be seen as a demonstration of momentum conservation. Given that the cannon exerts equal impulses on both the dog, Astro, and the cat, Beta, the system's momentum is conserved. The crucial insight to solving such problems is recognizing that if the time and force exerted by the cannon remain constant for both Astro and Beta, their impulses must also be equal. Since impulse is the product of force and time, we conclude that the change in momentum (I = mv) for each must be the same.

When teaching momentum conservation, it's beneficial to help students visualize and conceptualize the physical systems in question. Exercises that incorporate real-world scenarios, such as our example with Astro and Beta, can assist students in better relating to the concepts and remembering the principles behind them.

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

Two masses, \(m_1\) and \(m_2\), are connected by a string of negligible mass, which passes over a massless pulley, as shown in the figure. Assume \(m_1>m_2\). What is the acceleration \(a\) of \(m_1\) ? (A) \(a=\left(m_1-m_2\right) g /\left(m_1+m_2\right)\) (B) \(a=\left(m_1+m_2\right) g /\left(m_1-m_2\right)\) (C) \(a=\left(m_1 m_2\right) g /\left(m_1+m_2\right)\) (D) \(a=\left(m_2-m_1\right) g /\left(m_1+m_2\right)\) (E) \(a=\left(m_1-m_2\right) g /\left(m_1 m_2\right)\)

In the late twentieth century the Pioneer 10 and 11 space probes were passing through the Kuiper belt, a region beyond Neptune that contains dust, ice and other small bodies, and which is thought to be the origin of some comets. Pioneer 10 had a mass of \(240 \mathrm{~kg}\), was travelling at a velocity of \(12.2 \mathrm{~km} / \mathrm{s}\) and carried a dish antenna with radius \(R=1.73 \mathrm{~m}\). The spacecraft was observed to decelerate with \(a=8 \times 10^{-10} \mathrm{~m} / \mathrm{s}^2\). It is known that some gaseous nebulae have densities of about \(10^{-16} \mathrm{~kg} / \mathrm{m}^3\). Was the Pioneer deceleration consistent with this number?

cant copy graph Two students, Alice and Bob, decide to compute the power that the Earth's gravitational field expends on a block of mass \(m\) as the block slides down a frictionless inclined plane. Alice reasons: "The gravitational force pulling the block down the incline is \(F=m g \sin \theta\). The block's velocity at any given height \(h\) from the top of the incline is \(v=\sqrt{2 g h}\). Power is defined as force \(\times\) velocity. Therefore, the power is \(P=m g \sin \theta \sqrt{2 g h}\)." Bob reasons: "Power is \(\Delta W / \Delta t\). By the work-energy theorem, the change in work is the change in kinetic energy, but without friction \(\Delta W=m g h\). The change in time is \(\Delta t=\Delta v / a, \Delta v=\sqrt{2 g h}\) and \(a=g \sin \theta\). So \(\Delta t=\sqrt{2 g h} /(g \sin \theta)\). Therefore, \(P=m g h \times \frac{g \sin \theta}{\sqrt{2 g h}}=m g \sin \theta \sqrt{\frac{g h}{2}}\)." Alice and Bob look at each other and scratch their heads. Who is correct? \(\begin{array}{llll}\text { i. Alice } & \text { ii. Bob } & \text { iii. Neither iv. Both } & \text { v. The problem is imprecisely worded. }\end{array}\) (A) \(\mathrm{i}\) (B) ii (C) iii (D) iv (E) iv and \(v\)

You are sitting on a swing that is tied to a branch of a big tree above you. Consider the following forces: i. The force of gravity the Earth exerts on you ii. The force of gravity you exert on the Earth iii. The force the rope exerts on the swing iv. The force the swing exerts on the rope Which are action-reaction pairs? (A) Pair \(i\) and ii (B) Pair iii and iv (C) Pair i and iii (D) Pair ii and iv (E) Both pairs \(\mathrm{i}\) and ii and iii and iv

Which of the following are units of power? (Pascal is a unit of pressure.) i. watt ii. kilowatt \(\mathrm{hr}\) iii. newton \(\mathrm{m} / \mathrm{s}\) iv. kilowatt hr/day v. pascal \(\mathrm{m}^3 / \mathrm{s}\) (A) i (B) i and ii (C) ii and iii (D) iv and \(v\) (E) i, iii, iv and \(v\)

See all solutions

Recommended explanations on Physics Textbooks

View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.

Sign-up for free