/*! 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 9 In 0.750 s, a 7.00-kg block is p... [FREE SOLUTION] | 91Ó°ÊÓ

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In 0.750 s, a 7.00-kg block is pulled through a distance of 4.00 m on a frictionless horizontal surface, starting from rest. The block has a constant acceleration and is pulled by means of a horizontal spring that is attached to the block. The spring constant of the spring is 415 N/m. By how much does the spring stretch?

Short Answer

Expert verified
The spring stretches by 0.240 m.

Step by step solution

01

Determine Final Velocity

First, determine the final velocity of the block after it has been pulled through the 4.00 m distance in 0.750 s, using the formula for final velocity with constant acceleration:\[ v = u + at \]where \( u = 0 \) (initial velocity), \( t = 0.750 \) s (time), and \( v = \) final velocity. Rearrange it to find \( v \):\[ v = 0 + a \times 0.750 \]
02

Use Distance Formula

We can use the distance formula to relate acceleration and final velocity:\[ s = ut + \frac{1}{2}at^2 \]where \( s = 4.00 \) m, \( u = 0 \), \( t = 0.750 \) s. Plug in the values:\[ 4.00 = 0 + \frac{1}{2}a(0.750)^2 \]Solve for \( a \) to find the acceleration.
03

Solve for Acceleration

Using the equation from Step 2, solve for acceleration \( a \):\[ 4.00 = \frac{1}{2}a(0.750)^2 \]\[ 4.00 = \frac{1}{2}a(0.5625) \]\[ 4.00 = 0.28125a \]\[ a = \frac{4.00}{0.28125} = 14.22 \, \text{m/s}^2 \]
04

Determine Force on Block

Now that we have the acceleration, use Newton's Second Law to find the force exerted on the block:\[ F = ma \]where \( m = 7.00 \) kg and \( a = 14.22 \) m/s². Calculate the force:\[ F = 7.00 \times 14.22 = 99.54 \, \text{N} \]
05

Calculate Spring Stretch

The force exerted by the spring, \( F = kx \), must equal the force we calculated. Here, \( k = 415 \) N/m is the spring constant and \( x \) is the stretch of the spring:\[ 99.54 = 415x \]Solve for \( x \):\[ x = \frac{99.54}{415} = 0.240 \, \text{m} \]
06

Conclusion

The spring stretches by 0.240 m when the block is pulled through the distance of 4.00 m in 0.750 s.

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Key Concepts

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

Hooke's Law
Hooke's Law is an essential principle in physics that describes how springs behave. It tells us that the force needed to stretch or compress a spring by a certain distance is proportional to that distance. Mathematically, this is expressed as:\[ F = kx \]Where:
  • \( F \) is the force applied to the spring (in Newtons).
  • \( k \) is the spring constant (in N/m), indicating how stiff the spring is.
  • \( x \) is the distance the spring is stretched or compressed from its equilibrium position (in meters).
In this problem, Hooke's Law helps determine how much our spring stretches when a block is pulled. With a spring constant \( k \) of 415 N/m, the problem involves finding the extent of stretching needed to exert a force of 99.54 N. This shows that the spring’s resistance is overcome leading to the exact amount of stretch calculated as 0.240 meters.
Newton's Second Law
Newton's Second Law establishes the relationship between the net force acting on an object, its mass, and the acceleration produced. This is famously captured by the formula:\[ F = ma \]Where:
  • \( F \) represents the net force applied to an object (in Newtons).
  • \( m \) is the mass of the object (in kilograms).
  • \( a \) is the acceleration of the object (in \/m/s²).
In our exercise, the second law is crucial to find how much force is generated by the acceleration of a 7.00 kg block with an acceleration of 14.22 m/s². Using this simple equation, the force exerted on the block by the spring and any driving factors is computed to be 99.54 N. This equates to the force applied by the spring, illustrating the universal applicability of Newton's Law in predicting an object's response to forces.
Constant Acceleration
Constant acceleration indicates that an object's speed changes at a steady rate over time. This notion allows us to use a set of standard equations to predict the motion of objects subjected to uniform accelerations. The concept covers fundamental equations such as:
  • Final velocity \( v = u + at \)
  • Distance \( s = ut + \frac{1}{2}at^2 \)
In this scenario, we're informed that the block starts from rest. With these characteristics and a time frame of 0.750 seconds, we employed these equations to determine the block's movement and acceleration as it travelled 4 meters. This knowledge is pivotal to understanding how it linked to calculating the force required to stretch the spring.
Spring Force
Spring force refers to the force exerted by a spring upon any object that stretches or compresses it. As per Hooke's Law, the spring force is aligned with the product of the spring constant and the displacement from its rest position:\[ F = kx \]In our exercise, the spring is the instrument applying force to the block. With a spring constant \( k \) of 415 N/m and the force necessitated to move the 7 kg block as 99.54 N, the calculation shows how far the spring stretched from its natural position. Solving the equation, the spring force reveals a deformation of 0.240 meters. This step acknowledges that even though the movement is facilitated by constant acceleration, the spring's physical properties determine the precise details of the interaction involved.

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Most popular questions from this chapter

A cylindrically shaped piece of collagen (a substance found in the body in connective tissue) is being stretched by a force that increases from 0 to \(3.0 \times 10^{-2} \mathrm{N}\). The length and radius of the collagen are, respectively, 2.5 and \(0.091 \mathrm{cm},\) and Young's modulus is \(3.1 \times 10^{6} \mathrm{N} / \mathrm{m}^{2}\). (a) If the stretching obeys Hooke's law, what is the spring constant \(k\) for collagen? (b) How much work is done by the variable force that stretches the collagen? (See Section 6.9 for a discussion of the work done by a variable force.)

A spring is resting vertically on a table. A small box is dropped onto the top of the spring and compresses it. Suppose the spring has a spring constant of 450 N/m and the box has a mass of 1.5 kg. The speed of the box just before it makes contact with the spring is 0.49 m/s. (a) Determine the magnitude of the spring’s displacement at an instant when the acceleration of the box is zero. (b) What is the magnitude of the spring’s displacement when the spring is fully compressed?

Ssm A hand exerciser utilizes a coiled spring. A force of \(89.0 \mathrm{N}\) is required to compress the spring by \(0.0191 \mathrm{m} .\) Determine the force needed to compress the spring by \(0.0508 \mathrm{m}\).

An object attached to a horizontal spring is oscillating back and forth along a frictionless surface. The maximum speed of the object is \(1.25 \mathrm{m} / \mathrm{s},\) and its maximum acceleration is \(6.89 \mathrm{m} / \mathrm{s}^{2} .\) How much time elapses between an instant when the object's speed is at a maximum and the next instant when its acceleration is at a maximum?

The fan blades on a jet engine make one thousand revolutions in a time of 50.0 ms. Determine (a) the period (in seconds) and (b) the frequency (in Hz) of the rotational motion. (c) What is the angular frequency of the blades?

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