Math Problem Statement

A 2670 lb tractor drags a 355 lb box across level ground as shown in (Figure 1). The tractor has a tractive force of 446 lb . There is a 187 lb friction force between the box and the ground. Ignore air resistance.

Solution

In this problem, we need to analyze the forces acting on the box being dragged by the tractor. The scenario likely involves calculating either the net force, acceleration, or tension in the system.

Step-by-Step Analysis:

  1. Tractive Force: The tractor is applying a force of 446 lb to drag the box.

  2. Friction Force: The friction between the box and the ground is 187 lb, which resists the motion of the box.

  3. Net Force on the Box: The net force is the difference between the tractive force and the friction force, assuming the forces are aligned horizontally.

    Fnet=FtractiveFfrictionF_{\text{net}} = F_{\text{tractive}} - F_{\text{friction}}

    Substituting values:

    Fnet=446lb187lb=259lbF_{\text{net}} = 446 \, \text{lb} - 187 \, \text{lb} = 259 \, \text{lb}

  4. Weight of the Box: The weight of the box (355 lb) acts vertically and doesn’t contribute to horizontal motion but plays a role in the friction force.

  5. Acceleration: If we want to find the acceleration of the box, we would use Newton’s second law. First, we convert the weight of the box to mass in slugs, as follows (using g=32.2ft/s2g = 32.2 \, \text{ft/s}^2 for gravitational acceleration):

    mbox=355lb32.2ft/s211.03slugsm_{\text{box}} = \frac{355 \, \text{lb}}{32.2 \, \text{ft/s}^2} \approx 11.03 \, \text{slugs}

    Now, applying Newton's second law:

    F=ma    a=FnetmboxF = ma \implies a = \frac{F_{\text{net}}}{m_{\text{box}}}

    Substituting values:

    a=259lb11.03slugs23.49ft/s2a = \frac{259 \, \text{lb}}{11.03 \, \text{slugs}} \approx 23.49 \, \text{ft/s}^2

Summary of Results:

  • Net Force on the box: 259 lb.
  • Acceleration of the box: 23.49 ft/s².

Would you like to explore any of these points further or go into details on another concept?

Here are 5 related questions to consider:

  1. How does the frictional force change if the weight of the box increases?
  2. What would happen to the acceleration if the tractive force was doubled?
  3. How does air resistance typically affect problems like these?
  4. Can we calculate the coefficient of friction with the given data?
  5. How would the result change if the tractor was moving uphill?

Tip: Always remember that friction opposes motion, and its force depends on both the nature of the surfaces and the normal force.

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Math Problem Analysis

Mathematical Concepts

Newton's Laws of Motion
Force
Friction
Acceleration

Formulas

Net force: F_net = F_tractive - F_friction
Newton's Second Law: F = ma
Mass from weight: m = weight / g

Theorems

Newton's Second Law of Motion

Suitable Grade Level

High School (Grades 9-12)