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What is the minimum work needed to push a \(950-\mathrm{kg}\) car \(310 \mathrm{~m}\) up along a \(9.0^{\circ}\) incline? Ignore friction.

Short Answer

Expert verified
The minimum work needed is approximately 452,324 Joules.

Step by step solution

01

Understanding the Problem

The problem requires us to calculate the minimum work needed to push a car up a slope. Since friction is ignored, we only need to consider the component of gravitational force parallel to the incline.
02

Identify the Components

The weight of the car is given by the force due to gravity: \[ \text{Weight} = mg \]where \( m = 950 \, \text{kg} \) and \( g = 9.8 \, \text{m/s}^2 \). The angle of the incline is \( \theta = 9.0^{\circ} \).
03

Calculate the Gravitational Force Component

The component of the gravitational force parallel to the incline is:\[ F_{\parallel} = mg \sin(\theta) \]Substitute the known values:\[ F_{\parallel} = 950 \, \text{kg} \times 9.8 \, \text{m/s}^2 \times \sin(9.0^{\circ}) \].
04

Compute Sin Function

Calculate \( \sin(9.0^{\circ}) \), which is approximately \( 0.156434 \).
05

Substitute and Solve for Force

Substitute \( \sin(9.0^{\circ}) \) into the expression for the parallel force:\[ F_{\parallel} = 950 \, \text{kg} \times 9.8 \, \text{m/s}^2 \times 0.156434 = 1459.11 \, \text{N} \].
06

Calculate Work Done

Work done is the product of the force along the incline and the distance:\[ W = F_{\parallel} \times \text{distance} \]\[ W = 1459.11 \, \text{N} \times 310 \, \text{m} \].
07

Final Calculation

Substitute the values and calculate:\[ W = 452324.1 \, \text{Joules} \].
08

Answer Verification and Units

Verify that the units are consistent and that the calculated work is in joules, a unit of energy.

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Key Concepts

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

Gravitational Force
Gravitational force is a fundamental concept in physics and is the force of attraction between two masses. In the context of mechanics problems involving inclined planes, it is essential to understand how this force acts on objects. The gravitational force on an object can be calculated using the formula:
  • F = mg, where m is the mass of the object and g is the acceleration due to gravity, approximately 9.8 m/s².
When solving problems involving inclined planes, it's important to recognize that gravity acts directly downward, and we are often interested in its components relative to the incline. Knowing how to resolve the gravitational force into components is key:
  • Parallel component: This is the component along the plane, calculated as mg sin(θ).
  • Perpendicular component: This is the component perpendicular to the inclined plane, calculated as mg cos(θ).
By focusing on the parallel component, as seen in the car problem, it helps us determine the force needed to move an object upwards, emphasizing the direction of motion against gravity.
Inclined Planes
Inclined planes are flat surfaces tilted at an angle to the horizontal. These are commonly used in physics to simplify problems that involve motion and forces. Understanding how objects move on these surfaces is a fundamental part of mechanics.
When examining inclined planes, the angle of elevation plays a pivotal role because it affects how much force is needed to move an object. The steeper the plane, the greater the component of gravitational force acting along the plane. In the given problem, the plane is inclined at 9.0°, which modestly influences the force calculation.
In analyzing an inclined plane:
  • Decomposing forces into components is crucial.
  • We often focus on the parallel component to understand motion along the slope.
The simplification of ignoring friction helps emphasize the pure mechanics of gravitational force components and the inclination angle. Thus, problems involving inclined planes demonstrate fundamental physics principles, allowing students to practice resolving forces and calculating work done without the complexities of additional resistive forces.
Mechanics Problems
Mechanics problems, especially those involving forces and motion, are core to understanding physics. They provide insights into how different forces interact and influence motion.
In the presented exercise, we are confronted with a classic mechanics problem: calculating the work required to move an object along an inclined plane.
To solve such mechanics problems, a systematic approach is invaluable:
  • First, identify all forces acting on the object.
  • Decompose forces into components relative to the direction of motion, especially on inclined planes.
  • Utilize equations that relate these forces to solve for the desired quantity—in this case, work, where Work = Force × Distance.
Work is a measure of energy transfer and is calculated in joules. The conclusion of the exercise showcases how concepts from mechanics come together: understanding gravitational force, the geometry of inclined planes, and the principle of work and energy. These frameworks aid in solving complex physics problems and provide a foundational understanding necessary for more advanced topics.

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