Two masses, \(m_{1}=2.0 \mathrm{~kg}\) and \(m_{2}=3.0 \mathrm{~kg}\), are moving in the \(x y\) -plane. The velocity of their center of mass and the velocity of mass 1 relative to mass 2 are given by the vectors \(v_{\mathrm{cm}}=(-1.0,+2.4) \mathrm{m} / \mathrm{s}\) and \(v_{\mathrm{rel}}=(+5.0,+1.0) \mathrm{m} / \mathrm{s} .\) Determine a) the total momentum of the system b) the momentum of mass 1 , and c) the momentum of mass 2 .

Short Answer

Expert verified
The total momentum of the system is (-5.0, +12.0) kg.m/s. b) What is the momentum of mass 1? The momentum of mass 1 is (+6.0, -4.0) kg.m/s. c) What is the momentum of mass 2? The momentum of mass 2 is (-11.0, +16.0) kg.m/s.

Step by step solution

01

a) Total momentum of the system

To find the total momentum of the system (P_total), we will first add the masses together (M) and multiply it by the given center of mass velocity (v_cm): \(P_{\text{total}} = M \times v_{\text{cm}}\) \(M = m_1 + m_2 = 2.0 kg + 3.0 kg = 5.0 kg\) \(v_{\text{cm}} = (-1.0,+2.4) \frac{m}{s}\) So, \(P_{\text{total}} = (5.0 kg) \times (-1.0,+2.4) \frac{m}{s} = (-5.0,+12.0) \frac{kg.m}{s}\)
02

b) Momentum of mass 1

To find the momentum of mass 1 (P_1), we need to first find its velocity (v_1). To calculate this, we will use the relative velocity of mass 1 to mass 2 (v_rel) and the center of mass velocity (v_cm). We know that: \(v_{\text{rel}} = v_1 - v_2\) \(v_1 = v_{\text{rel}} + v_2\) Now we can find the velocity of mass 2 (v_2) using the center of mass velocity: \(v_{\text{cm}} = \frac{m_1 v_1 + m_2 v_2}{m_1 + m_2}\) \(v_2 = \frac{v_{\text{cm}}(m_1 + m_2) - m_1 v_1}{m_2}\) Substitute the values: \(v_2 = \frac{(-1.0,+2.4)(5.0) - 2.0 v_1}{3.0}\) \(v_2 = \frac{(-5.0,+12.0) - 2.0 v_1}{3.0}\) Now, substitute \(v_2\) back into the equation for \(v_1\): \(v_1 = (+5.0,+1.0) + \frac{(-5.0,+12.0) - 2.0 v_1}{3.0}\) Solving for \(v_1\), we get: \(v_1 = (+3.0,-2.0) \frac{m}{s}\) Now, we can find the momentum of mass 1 by multiplying its mass with its velocity: \(P_1 = m_1 \times v_1 = (2.0 kg) \times (+3.0,-2.0) \frac{m}{s} = (+6.0,-4.0) \frac{kg.m}{s}\)
03

c) Momentum of mass 2

Now that we have the momentum of mass 1, we can use the total momentum of the system to determine the momentum of mass 2 (P_2): \(P_{\text{total}} = P_1 + P_2\) \(P_2 = P_{\text{total}} - P_1 = (-5.0,+12.0) \frac{kg.m}{s} - (+6.0,-4.0) \frac{kg.m}{s} = (-11.0,+16.0) \frac{kg.m}{s}\)

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!

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

A uniform chain with a mass of \(1.32 \mathrm{~kg}\) per meter of length is coiled on a table. One end is pulled upward at a constant rate of \(0.47 \mathrm{~m} / \mathrm{s}\). a) Calculate the net force acting on the chain. b) At the instant when \(0.15 \mathrm{~m}\) of the chain has been lifted off the table, how much force must be applied to the end being raised?

You find yourself in the (realistic?) situation of being stuck on a 300 -kg raft (including yourself) in the middle of a pond with nothing but a pile of 7 -kg bowling balls and 55 -g tennis balls. Using your knowledge of rocket propulsion, you decide to start throwing balls from the raft to move toward shore. Which of the following will allow you to reach the shore faster? a) throwing the tennis balls at \(35 \mathrm{~m} / \mathrm{s}\) at a rate of 1 tennis ball per second b) throwing the bowling balls at \(0.5 \mathrm{~m} / \mathrm{s}\) at a rate of 1 bowling ball every \(3 \mathrm{~s}\) c) throwing a tennis ball and a bowling ball simultaneously, with the tennis ball moving at \(15 \mathrm{~m} / \mathrm{s}\) and the bowling ball moving at \(0.3 \mathrm{~m} / \mathrm{s}\), at a rate of 1 tennis ball and 1 bowling ball every \(4 \mathrm{~s}\) d) not enough information to decide

A man standing on frictionless ice throws a boomerang, which returns to him. Choose the correct statement::: a) Since the momentum of the man-boomerang system is conserved, the man will come to rest holding the boomerang at the same location from which he threw it. b) It is impossible for the man to throw a boomerang in this situation. c) It is possible for the man to throw a boomerang, but because he is standing on frictionless ice when he throws it, the boomerang cannot return. d) The total momentum of the man-boomerang system is not conserved, so the man will be sliding backward holding the boomerang after he catches it.

A toy car of mass \(2.0 \mathrm{~kg}\) is stationary, and a child rolls a toy truck of mass 3.5 kg straight toward it with a speed of \(4.0 \mathrm{~m} / \mathrm{s}\) a) What is the velocity of the center of mass of the system consisting of the two toys? b) What are the velocities of the truck and the car with respect to the center of mass of the system consisting of the two toys?

An 80 -kg astronaut becomes separated from his spaceship. He is \(15.0 \mathrm{~m}\) away from it and at rest relative to it. In an effort to get back, he throws a \(500-\mathrm{g}\) object with a speed of \(8.0 \mathrm{~m} / \mathrm{s}\) in a direction away from the ship. How long does it take him to get back to the ship? a) \(1 \mathrm{~s}\) b) \(10 \mathrm{~s}\) c) \(20 \mathrm{~s}\) d) \(200 \mathrm{~s}\) e) \(300 \mathrm{~s}\)

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