A sewing machine needle moves with a rapid vibratory motion, rather like SHM, as it sews a seam. Suppose the needle moves \(8.4 \mathrm{mm}\) from its highest to its lowest position and it makes 24 stitches in 9.0 s. What is the maximum needle speed?

Short Answer

Expert verified
Answer: The maximum speed of the sewing machine needle is 0.1408 m/s.

Step by step solution

01

Understanding the given information

We are given the following information: - Amplitude (A): The distance from the highest to the lowest position, which is \(8.4 \mathrm{mm}\) - Number of stitches: 24 - Time taken to perform the stitches (t): 9.0 s
02

Calculate the time period for one full oscillation

One full oscillation occurs when the needle completes one up-down cycle. The time period for one full oscillation (T) can be calculated by dividing the total time taken by the number of stitches as each stitch corresponds to a single oscillation: \(T=\frac{t}{\text{number of stitches}}\) Plug in the values: \(T = \frac{9.0 \mathrm{s}}{24}\) \(T = 0.375 \mathrm{s}\)
03

Determine the angular frequency

The angular frequency (\(\omega\)) can be calculated using the formula: \( \omega = \frac{2 \pi}{T} \) Plug in the value for T: \( \omega = \frac{2 \pi}{0.375 \mathrm{s}} \) \( \omega = 16.76 \ \text{s}^{-1} \)
04

Calculate the maximum needle speed

The maximum speed (vmax) of the needle in SHM can be found using the formula: \( \mathrm{v_{max}} = A \omega \) Plug in the values for A and \(\omega\): \( \mathrm{v_{max}} = (8.4 \mathrm{mm})(16.76 \ \text{s}^{-1})\) \( \mathrm{v_{max}} = 140.8 \ \text{mm} \ \text{s}^{-1} \)
05

Express the answer in the right unit

The maximum needle speed can be converted from \(\text{mm} \ \text{s}^{-1}\) to \(\text{m} \ \text{s}^{-1}\): \( \mathrm{v_{max}} = 140.8 \ \text{mm} \ \text{s}^{-1} \times \frac{1 \text{m}}{1000 \text{mm}} = 0.1408 \ \text{m} \ \text{s}^{-1}\) The maximum needle speed is \(0.1408 \ \text{m} \ \text{s}^{-1}\).

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Most popular questions from this chapter

A \(230.0-\mathrm{g}\) object on a spring oscillates left to right on a frictionless surface with a frequency of \(2.00 \mathrm{Hz}\). Its position as a function of time is given by \(x=(8.00 \mathrm{cm})\) sin \(\omega t\) (a) Sketch a graph of the elastic potential energy as a function of time. (b) The object's velocity is given by \(v_{x}=\omega(8.00 \mathrm{cm}) \cos \omega t .\) Graph the system's kinetic energy as a function of time. (c) Graph the sum of the kinetic energy and the potential energy as a function of time. (d) Describe qualitatively how your answers would change if the surface weren't frictionless.
(a) Sketch a graph of \(x(t)=A \sin \omega t\) (the position of an object in SHM that is at the equilibrium point at \(t=0\) ). (b) By analyzing the slope of the graph of \(x(t),\) sketch a graph of $v_{x}(t) .\( Is \)v_{x}(t)$ a sine or cosine function? (c) By analyzing the slope of the graph of \(v_{x}(t),\) sketch \(a_{x}(t)\) (d) Verify that \(v_{x}(t)\) is \(\frac{1}{4}\) cycle ahead of \(x(t)\) and that \(a_{x}(t)\) is \(\frac{1}{4}\) cycle ahead of \(v_{x}(t) .\) (W) tutorial: sinusoids)
A pendulum is made from a uniform rod of mass \(m_{1}\) and a small block of mass \(m_{2}\) attached at the lower end. (a) If the length of the pendulum is \(L\) and the oscillations are small, find the period of the oscillations in terms of \(m_{1}, m_{2}, L,\) and \(g .\) (b) Check your answer to part (a) in the two special cases \(m_{1} \gg m_{2}\) and \(m_{1}<<m_{2}\).
It takes a flea \(1.0 \times 10^{-3}\) s to reach a peak speed of $0.74 \mathrm{m} / \mathrm{s}$ (a) If the mass of the flea is \(0.45 \times 10^{-6} \mathrm{kg},\) what is the average power required? (b) Insect muscle has a maximum output of 60 W/kg. If \(20 \%\) of the flea's weight is muscle, can the muscle provide the power needed? (c) The flea has a resilin pad at the base of the hind leg that compresses when the flea bends its leg to jump. If we assume the pad is a cube with a side of \(6.0 \times 10^{-5} \mathrm{m},\) and the pad compresses fully, what is the energy stored in the compression of the pads of the two hind legs? The Young's modulus for resilin is $1.7 \times 10^{6} \mathrm{N} / \mathrm{m}^{2} .$ (d) Does this provide enough power for the jump?
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