/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Problem 55 A spring of constant \(k=290 \ma... [FREE SOLUTION] | 91Ó°ÊÓ

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A spring of constant \(k=290 \mathrm{~N} / \mathrm{m}\) is used to launch a \(1.9-\mathrm{kg}\) block along a horizontal surface whose coefficient of sliding friction is \(0.29\). If the spring is compressed \(22 \mathrm{~cm}\), how far does the block slide?

Short Answer

Expert verified
Solve the equation obtained in Step 3 for \(d\), which gives the distance the block slides.

Step by step solution

01

Calculate Potential Energy of Spring

Start by calculating the initial potential energy \(E_{p,i}\) stored in the spring when it is compressed 22 cm or 0.22 m. The formula for the potential energy in the spring is \(E_{p,i} = 0.5 * k * x^2\), where \(k = 290 N/m\) is the spring constant and \(x = 0.22 m\) is the compression distance.
02

Calculate Work Done Against Friction

Next, calculate the work \(W_f\) done against friction as the block slides. The work done against friction is given by \(W_f = f * d\), where \(f = \mu * N\) is the frictional force, \(N = m*g\) is the normal force, and \(d\) is the distance block slides. However, we do not know \(d\), so leave it as it is. Plug in the values of \(m = 1.9 kg\) for the mass of the block, \(g = 9.81 m/s^2\) for the acceleration due to gravity, and \(µ = 0.29\) for the coefficient of sliding friction.
03

Set Up and Solve Energy Balance Equation

Write the conservation of energy equation: initial potential energy equals final kinetic energy plus work done against friction, \(E_{p,i} = E_{k,f} + W_f\). The block has no final kinetic energy because it comes to a stop, hence \(E_{k,f} = 0\). Thus, the equation becomes \(E_{p,i} = W_f\). Now, substitute the formulations from Step 1 and Step 2 into this equation and solve for \(d\), the distance the block slides.

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Key Concepts

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

Spring Potential Energy
When you compress a spring, you do work on it, storing energy in the form of spring potential energy. This energy is described by the equation for potential energy in a spring, which is \( E_{p} = \frac{1}{2} k x^2 \), where \( k \) is the spring constant and \( x \) is the compression or extension from the spring's equilibrium position. The higher the spring constant, the stiffer the spring, and the more work is required to compress or extend it by a certain amount.

In our example, a spring with constant \( k = 290 \, N/m \) is compressed \( 22 \, cm \) or \( 0.22 \,m\). Plugging these values into the equation yields the initial potential energy stored in the spring. This energy is what propels the block forward once the spring is released. Understanding the relationship between spring compression and stored energy is crucial when analyzing motion initiated by spring force.
Work-Energy Principle
The work-energy principle is a fundamental concept in physics that connects the work done on an object with the change in its kinetic energy. According to this principle, the net work done by forces on an object is equal to the change in its kinetic energy. In mathematical terms, \( W_{net} = \Delta E_{k} \).

For our physics problem, once the spring is released, the only work done on the block is the work done against friction, which opposes the block's motion. Friction does negative work and thus removes kinetic energy from the block until it stops moving. The work done by the friction can be calculated using the formula \( W_f = f * d \), where \( f \) is the frictional force and \( d \) is the distance over which the force acts. As the block slides and eventually comes to a stop, its kinetic energy decreases to zero, meaning all the energy stored in the spring is consumed by the work done against friction.
Coefficient of Sliding Friction
The coefficient of sliding friction, often denoted by the Greek letter \( \mu \), is a dimensionless number that represents the ratio of the force of friction between two bodies and the force pressing them together. It is a measure of how easily one surface slides over another.

The frictional force \( f \) can be expressed as the product of the coefficient of sliding friction \( \mu \) and the normal force \( N \) acting on the object. In most cases, this normal force is simply the weight of the object due to gravity, \( N = m * g \), where \( m \) is the mass and \( g \) the acceleration due to gravity.

With a higher \( \mu \), more work has to be done to move an object across a surface, resulting in a shorter distance travelled for a given amount of initial energy. In our scenario, the block experiences a frictional force based on its mass, the gravitational force (\( 1.9 \, kg \) and \( 9.81 \, m/s^2 \), respectively), and the given coefficient of sliding friction of \( 0.29 \). This interaction plays a vital role in determining how far the block will slide after being launched by the spring.

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Most popular questions from this chapter

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