Physics Chapter: Hooke's Law and Elasticity
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Physics Chapter: Hooke's Law and Elasticity

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Questions and Answers

How is the elastic constant (k) related to the restoring force (F) and displacement (s)?

The elastic constant (k) is the proportionality constant in Hooke’s law, relating the restoring force (F) to the displacement (s) from the equilibrium position as F = k * s.

What is the formula to calculate the displacement (s) when a spring is stretched or compressed?

The displacement (s) is calculated as s = l - l_0, where l is the new length and l_0 is the original length of the spring.

In the context of SHM, what happens to the velocity and acceleration when the displacement is maximal?

When the displacement is maximal, the velocity is zero while the acceleration is maximal, directed towards the equilibrium position.

Explain the significance of the negative sign in the relation a ∝ -s in SHM.

<p>The negative sign in a ∝ -s indicates that the acceleration is always directed opposite to the displacement, implying that the system seeks to return to equilibrium.</p> Signup and view all the answers

What is the SI unit of the elastic constant (k), and why is it important?

<p>The SI unit of the elastic constant (k) is newton per metre (N m^-1), which is important for quantifying how stiff or flexible a material is under deformation.</p> Signup and view all the answers

What is the SI unit of amplitude in simple harmonic motion?

<p>Metre</p> Signup and view all the answers

If the frequency of a simple harmonic oscillator is increased, what happens to its period?

<p>It decreases</p> Signup and view all the answers

What is the relationship between the period of a pendulum and its length?

<p>Period is directly proportional to the square root of the length</p> Signup and view all the answers

How is the frequency (f) of an oscillator calculated from its period (T)?

<p>f = 1/T</p> Signup and view all the answers

In calculating the period of a simple pendulum, what effect does increasing the acceleration due to gravity have?

<p>Decreases the period</p> Signup and view all the answers

What is the correct formula for calculating the elastic constant (k) of a spring?

<p>k = |mg/l|</p> Signup and view all the answers

What is the angular frequency (ω) of an oscillator related to its elastic constant (k) and mass (m)?

<p>ω = √(k/m)</p> Signup and view all the answers

Which variable can be plotted on the y-axis to analyze the relationship between the length of a pendulum and its period squared?

<p>T^2</p> Signup and view all the answers

What precautions should be taken during the pendulum experiment to ensure valid results?

<p>Ensure the oscillation is in one plane</p> Signup and view all the answers

If a pendulum's length is doubled, what effect does this have on its period?

<p>The period doubles</p> Signup and view all the answers

What is the relationship between force (F) and displacement (s) according to Hooke's Law?

<p>Force is directly proportional to displacement.</p> Signup and view all the answers

If the elastic constant (k) is determined to be 1.47×10^5 N m^(-1), what does this indicate about the spring's behavior?

<p>The spring is extremely rigid.</p> Signup and view all the answers

When a spring is compressed from its original length of 30 mm to 24 mm, what is the displacement (s) calculated?

<p>6 mm</p> Signup and view all the answers

In the context of simple harmonic motion (SHM), what occurs when the displacement reaches its maximum?

<p>Acceleration is maximal and velocity is zero.</p> Signup and view all the answers

If a spring is compressed by a force of 882 N resulting in a displacement of -6 mm, what is the elastic constant (k)?

<p>14700 N m^(-1)</p> Signup and view all the answers

Which of the following statements accurately describes SHM in terms of acceleration?

<p>Acceleration is always directed towards the equilibrium position.</p> Signup and view all the answers

What happens to the velocity of an object in SHM when it passes through the equilibrium position?

<p>Velocity is maximal.</p> Signup and view all the answers

In Hooke's Law, which factor directly influences the restoring force experienced by a spring?

<p>The elastic constant (k).</p> Signup and view all the answers

Which of the following scenarios best exemplifies simple harmonic motion?

<p>A pendulum swinging back and forth.</p> Signup and view all the answers

How does the displacement (s) change as a spring is stretched according to Hooke's Law?

<p>It increases in proportion to the force applied.</p> Signup and view all the answers

Study Notes

Elasticity and Hooke's Law

  • When an object is deformed (stretched, bent, compressed), the restoring force (F) is proportional to the displacement (s) from its equilibrium position.
  • The elastic constant (k) relates force and displacement under Hooke's law with SI unit of N m⁻¹.
  • Displacement is defined as (s = (l - l_0)), where (l_0) = natural length and (l) = new length.
  • Hooke's law formula: (F = k(l - l_0)).

Sample Problem on Elastic Constant

  • Calculate elastic constant (k) when a 90 kg mass compresses a spring from 30 mm to 24 mm.
  • With (g = 9.8 , m/s^2), use (k = |mg/s|) to find (k = |882 / (-6 \times 10^{-3})| = 1.47 \times 10^5 , N/m).

Simple Harmonic Motion (SHM)

  • SHM is periodic motion where acceleration is proportional to and directed towards the equilibrium position; expressed as (a \propto -s).
  • Key SHM characteristics:
    • At zero displacement, acceleration and forces are zero; velocity is maximal.
    • At maximal displacement, acceleration is maximal; velocity is zero.

Parameters of SHM

  • Amplitude (A): Maximum distance from equilibrium; measured in meters (m).
  • Frequency (f): Number of cycles per time; measured in hertz (Hz); (f = \text{number of oscillations/time taken}).
  • Period (T): Time for one complete oscillation; related to frequency (f) by (T = 1/f) or (T = 2\pi/\omega).

Sample Problems on SHM and Pendulum

  • Example with a 500 g mass causing a 25 cm extension on a spring:

    • Elastic constant (k) found to be (19.6 , N/m).
  • Determine frequency of oscillation with a 200 g mass:

    • Evaluate angular frequency ((\omega = \sqrt{k/m})).
    • Period and frequency calculated to be (T = 0.635 , s) and (f \approx 1.6 , Hz).

Pendulum Motion

  • The period of a simple pendulum ((T)) depends on its length and gravity:
    • (T \propto \sqrt{l}).
    • Increasing length increases period; decreasing gravity increases period.

Sample Pendulum Problem

  • Calculate period for a pendulum of 50 cm:
    • Using (T = 2\pi\sqrt{l/g}) results in (T \approx 1.4 , s).

Experimental Setup for Pendulum

  • Apparatus includes pendulum bob, string, and measuring tools.
  • Procedure involves measuring bob diameter, setting string length, swinging the pendulum, and timing oscillations.

Data Collection and Analysis

  • Calculate periodic time (T) for various lengths, and determine (T^2).
  • Plot graph of length ((l)) vs. (T^2) shows linear relationship; slope provides acceleration due to gravity ((g)).

Experimental Precautions

  • Ensure small angle (less than 5°) for SHM validity.
  • Pendulum should oscillate in one plane with minimal air resistance and constant string length.
  • Repeated trials enhance accuracy; use of different masses demonstrates periodic time independence from mass.

Elasticity and Hooke's Law

  • When an object is deformed (stretched, bent, compressed), the restoring force (F) is proportional to the displacement (s) from its equilibrium position.
  • The elastic constant (k) relates force and displacement under Hooke's law with SI unit of N m⁻¹.
  • Displacement is defined as (s = (l - l_0)), where (l_0) = natural length and (l) = new length.
  • Hooke's law formula: (F = k(l - l_0)).

Sample Problem on Elastic Constant

  • Calculate elastic constant (k) when a 90 kg mass compresses a spring from 30 mm to 24 mm.
  • With (g = 9.8 , m/s^2), use (k = |mg/s|) to find (k = |882 / (-6 \times 10^{-3})| = 1.47 \times 10^5 , N/m).

Simple Harmonic Motion (SHM)

  • SHM is periodic motion where acceleration is proportional to and directed towards the equilibrium position; expressed as (a \propto -s).
  • Key SHM characteristics:
    • At zero displacement, acceleration and forces are zero; velocity is maximal.
    • At maximal displacement, acceleration is maximal; velocity is zero.

Parameters of SHM

  • Amplitude (A): Maximum distance from equilibrium; measured in meters (m).
  • Frequency (f): Number of cycles per time; measured in hertz (Hz); (f = \text{number of oscillations/time taken}).
  • Period (T): Time for one complete oscillation; related to frequency (f) by (T = 1/f) or (T = 2\pi/\omega).

Sample Problems on SHM and Pendulum

  • Example with a 500 g mass causing a 25 cm extension on a spring:

    • Elastic constant (k) found to be (19.6 , N/m).
  • Determine frequency of oscillation with a 200 g mass:

    • Evaluate angular frequency ((\omega = \sqrt{k/m})).
    • Period and frequency calculated to be (T = 0.635 , s) and (f \approx 1.6 , Hz).

Pendulum Motion

  • The period of a simple pendulum ((T)) depends on its length and gravity:
    • (T \propto \sqrt{l}).
    • Increasing length increases period; decreasing gravity increases period.

Sample Pendulum Problem

  • Calculate period for a pendulum of 50 cm:
    • Using (T = 2\pi\sqrt{l/g}) results in (T \approx 1.4 , s).

Experimental Setup for Pendulum

  • Apparatus includes pendulum bob, string, and measuring tools.
  • Procedure involves measuring bob diameter, setting string length, swinging the pendulum, and timing oscillations.

Data Collection and Analysis

  • Calculate periodic time (T) for various lengths, and determine (T^2).
  • Plot graph of length ((l)) vs. (T^2) shows linear relationship; slope provides acceleration due to gravity ((g)).

Experimental Precautions

  • Ensure small angle (less than 5°) for SHM validity.
  • Pendulum should oscillate in one plane with minimal air resistance and constant string length.
  • Repeated trials enhance accuracy; use of different masses demonstrates periodic time independence from mass.

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Description

Explore the concepts of Hooke's Law and elasticity in this quiz based on physics principles. Understand the relationship between restoring force and displacement, and learn about the elastic constant. Test your knowledge on the mathematical application and significance of elasticity in real-world scenarios.

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