In a butcher shop, a horizontal steel bar of mass \(4.00 \mathrm{~kg}\) and length \(1.20 \mathrm{~m}\) is supported by two vertical wires attached to its ends. The butcher hangs a sausage of mass \(2.40 \mathrm{~kg}\) from a hook that is at a distance of \(0.20 \mathrm{~m}\) from the left end of the bar. What are the tensions in the two wires?

Short Answer

Expert verified
Answer: The tension in the left wire (T1) is 47.08 N, and the tension in the right wire (T2) is 23.536 N.

Step by step solution

01

Identify the forces acting on the steel bar and the torque#

The forces acting on the steel bar are: 1. The weight of the bar: \(W_b = m_b \cdot g = 4.00 \,\text{kg} \cdot 9.81 \,\text{m/s}^2\) 2. The weight of the sausage: \(W_s = m_s \cdot g = 2.40 \,\text{kg} \cdot 9.81 \,\text{m/s}^2\) 3. The tension in the left wire: \(T_1\) 4. The tension in the right wire: \(T_2\) The torques caused by these forces are: 1. The torque due to the weight of the bar: \(\tau_b = W_b \cdot d_b\), where \(d_b\) is the distance from the pivot point to the center of mass of the bar. 2. The torque due to the weight of the sausage: \(\tau_s = W_s \cdot d_s\), where \(d_s=0.20 \,\text{m}\) is given. 3. The torque due to the tension in the left wire: \(\tau_1 = T_1 \cdot d_1\), where \(d_1 = 0\) since the left wire is the pivot point. 4. The torque due to the tension in the right wire: \(\tau_2 = T_2 \cdot d_2\), where \(d_2\) is the distance from the pivot point to the right wire attachment.
02

Calculate the weight of the bar and the sausage#

Calculate the weight of the bar \(W_b\) and the weight of the sausage \(W_s\): \(W_b = 4.00 \,\text{kg} \cdot 9.81 \,\text{m/s}^2 = 39.24 \,\text{N}\) \(W_s = 2.40 \,\text{kg} \cdot 9.81 \,\text{m/s}^2 = 23.544 \,\text{N}\)
03

Calculate the distances for torques#

To calculate the torques, we need the distances to the center of mass of the bar (\(d_b\)) and the distance from the left wire to the right wire (\(d_2\)): \(d_b = \dfrac{1.20 \,\text{m}}{2} = 0.60 \,\text{m}\) \(d_2 = 1.20 \,\text{m}\)
04

Set up the equilibrium equations#

We have two equilibrium equations: one for the sum of forces, and another one for the sum of torques: 1. Sum of forces equation: \(T_1 - T_2 = W_s\) 2. Sum of torques equation: \(\tau_b + \tau_s = \tau_2\) Calculating the torques: \(\tau_b = W_b \cdot d_b = 39.24 \,\text{N} \cdot 0.60 \,\text{m} = 23.544 \,\text{Nm}\) \(\tau_s = W_s \cdot d_s = 23.544 \,\text{N} \cdot 0.20 \,\text{m} = 4.7 \,\text{Nm}\) \(\tau_2 = T_2 \cdot d_2\) Substitute the torques into the sum of torques equation: \(23.544 \,\text{Nm} + 4.7 \,\text{Nm} = T_2 \cdot 1.20\, \text{m}\)
05

Solve for tensions in the left and right wires#

Solve the sum of torques equation for \(T_2\): \(T_2 = \dfrac{23.544 \,\text{Nm} + 4.7 \,\text{Nm}}{1.20 \,\text{m}} = 23.536 \,\text{N}\) Now, we can solve the sum of forces equation for \(T_1\): \(T_1 - T_2 = W_s\) \(T_1 = T_2 + W_s = 23.536 \,\text{N} + 23.544 \,\text{N} = 47.08 \,\text{N}\) Thus, the tension in the left wire (\(T_1\)) is \(47.08\, \text{N}\) and the tension in the right wire (\(T_2\)) is \(23.536\, \text{N}\).

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

11.7 A \(15-\mathrm{kg}\) child sits on a playground seesaw, \(2.0 \mathrm{~m}\) from the pivot. A second child located \(1.0 \mathrm{~m}\) on the other side of the pivot would have to have a mass of _________ to lift the first child off the ground. a) greater than \(30 \mathrm{~kg} \quad\) c) equal to \(30 \mathrm{~kg}\) b) less than \(30 \mathrm{~kg}\)

A uniform ladder \(10.0 \mathrm{~m}\) long is leaning against a frictionless wall at an angle of \(60.0^{\circ}\) above the horizontal. The weight of the ladder is \(20.0 \mathrm{lb} . \mathrm{A} 61.0-\mathrm{lb}\) boy climbs \(4.00 \mathrm{~m}\) up the ladder. What is the magnitude of the frictional force exerted on the ladder by the floor?

You have a meter stick that balances at the \(55-\mathrm{cm}\) mark. Is your meter stick homogeneous?

In the absence of any symmetry or other constraints on the forces involved, how many unknown force components can be determined in a situation of static equilibrium in each of the following cases? a) All forces and objects lie in a plane. b) Forces and objects are in three dimensions. c) Forces act in \(n\) spatial dimensions.

An object is restricted to movement in one dimension. Its position is specified along the \(x\) -axis. The potential energy of the object as a function of its position is given by \(U(x)=a\left(x^{4}-2 b^{2} x^{2}\right),\) where \(a\) and \(b\) represent positive numbers. Determine the location(s) of any equilibrium point(s), and classify the equilibrium at each point as stable, unstable, or neutral.

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