Shm Definition and 502 Threads

  1. M

    SHM problem with Momentum and Energy

    Homework Statement A 1.00kg block is attached to a horizontal spring with spring constant 2500N/m. The block is at rest on a frictionless surface. A 10g bullet is fired into the block, in the face opposite the spring, and sticks. a. What was the bullet's speed if the subsequent...
  2. R

    Solve Oscillations (SHM) Homework Statement: 76.7628 N/m & 51.0543 m

    Homework Statement I'm trying to solve this problem: http://img824.imageshack.us/img824/3513/prob1r.jpg The Attempt at a Solution I rearranged the equation T=2π√m/k to find the spring constant: k= \frac{m}{\left( \frac{T}{2 \pi} \right)^2} = \frac{70}{\left( \frac{6}{2 \pi}...
  3. J

    Finding Mass in SHM with Known Spring Constant and Velocity

    Homework Statement A block of unknown mass is attached to a spring with a spring constant 9.00 N/m and undergoes simple harmonic motion, along the x axis, with an amplitude of 10.0 cm. When the mass is halfway between its equilibrium position and its maximum positive displacement, its...
  4. J

    Rewriting SHM equation from a function of sin(wt) and cos(wt) to just cos(wt-∅)

    Homework Statement Rewrite the equation of motion x(t) = 2cos(wt) - 2sin(wt) in the form x(t) = C cos(wt-∅) Homework Equations The Attempt at a Solution I am able to work out the constant C as it is just the magnitude of the sin and cos function, C = (2^2 + 2^2)^1/2 = √8...
  5. binbagsss

    SHM: Vertical Displacement Above Equilibrium

    SHM - VERTICAL Surely whether you consider the motion used to establish the SHM system, or the motion as soon as the system is released you should derive the same equation. DISPLACEMENT BELOW EQUILLBRIUM. However, consider a verticle spring with particle attached hanging in equilibrium...
  6. binbagsss

    SHM spring system, Tension direction confusion.

    Say a spring is on a horizontal table, and the particle is initially at the midpoint of the spring in equilibrium, and then the particle is displaced to one side. I have attached a diagram, let this side be more to A. Then I am confused as to which direction the tension in both sides of...
  7. S

    Where is the Center of SHM in a Light Elastic String System?

    Homework Statement One end of a light elastic string having a natural length of 'a' and elastic modulus 'mg' is attached to 'm' mass and the other end to point 'O'. Then the mass is projected upwards.Where is the center of SHM? Homework Equations ω=angular velocity F=ma from...
  8. M

    What is the velocity of a block in SHM involving a spring after a given time?

    Homework Statement A 1.6-kg block on a horizontal frictionless surface is attached to a spring whose force constant is 190 N/m. The block is pulled from its equilibrium position at x = 0 m to a displacement x = +0.080 m and is released from rest. The block then executes simple harmonic motion...
  9. S

    Why Does Spring Constant Decrease with Increased Load?

    Homework Statement Ive worked out all of my values for my shm assignment. In the table of results i have found that my spring constant decreases with load applied. Im stuggling to come with a good reason for this. Number Mass (kg) Spring displacement (m) Spring constant (N/m) 1 0.05 0 n/a 2...
  10. G

    Period for SHM of a block on a spring shot by a bullet

    So I've been working on this problem for a while and can't seem to come up with anything and I don't really understand why I'm wrong in what I did. I could just get the answer online, but I actually want to understand what's happening. Homework Statement A rifle bullet with mass 8.12g and...
  11. M

    Few Problems (Waves, Elasticity, SHM)

    1. Homework Statement : Hello PF! Here are a few problems I'm stuck on. 1. When a tuning fork and a source of frequency 200 Hz are sounded together, 4 beats/sec are heard. When the tuning fork is loaded with some wax, again 4 beats/sec are heard. Then the original frequency of the fork was...
  12. M

    SHM ODE Problem: Finding Y General

    Homework Statement I've got y'' - ω2y = sin(ωx) + sinh(ωx) where y(a) = A, y(b) = B Homework Equations The Attempt at a Solution Yc = C1 Sinh(ωx) + C2 Cosh(ωx) and I got my Yp to be -1/2*sin(ωx) + 1/2*sinh(ωx) I'm not sure about getting the Y general. Any pointers...
  13. A

    How Do You Determine the Frequency of a Mass Connected to Four Springs?

    Homework Statement The mass is connected to 4 springs, each connected to a corner of a square with sides √2 a. The springs have spring constants k and natural length a/2. Show the frequency of the mass when it is displaced by d << a towards one of the corners is √(3k/m) Homework...
  14. O

    SHM: Different Final Answers When Using Energy Conversation & Trigonometry

    1. The Question from Text: "A forest playground has a tyre hanging from a tree branch. The tyre behaves like a pendulum, with a rope of 4.0 metres length, and the tyres mass 15 kg. A child of mass 45 kg swings on the tyre by pulling it 3.0 metres to one side and leaping on. What is the maximum...
  15. Saitama

    How Do You Calculate Amplitude and Time Period in SHM Problems?

    Homework Statement Question 1) In the figure below, k=100 N/m, M=1 kg and F=10N. A sharp blow by some external agent imparts the speed of 2 m/s to the block towards left. Find the amplitude of the resulting simple harmonic motion. Question 2) The string and the spring shown in the...
  16. O

    SHM: Deriving x = A cos(wt) & Intuitive Understanding

    Short story: How does one go about to derive x = a cos(wt)? The way it is derived in my book is from the "SHM Diagram" file that I have uploaded but it seems that the diagram is incorrect as it does not correspond to the expression. Also, why is the Amplitude in the expression constant when the...
  17. N

    Fluid Mechanics and SHM of spring

    Homework Statement Fluid Mechanics problem: http://i.imgur.com/dlAO6.jpg SHM of spring problem: http://i.imgur.com/7AOMR.jpg Homework Equations Fluid mechanic problem; Bernoulli's principle A1v1=A2v2 v= velocity A= cross sectional area R= flow rate SHM of spring problem; x(t)=Acos(ωt+∅)The...
  18. S

    Relationship betwen SHM frequency and harmonic oscillator freq.

    Homework Statement Relate the frequency of a harmonic oscillator (spring) to that of a simple harmonic oscillator (pendulum) Show all derivations. Homework Equations pendulum: f=(1/(2∏))√(g/L) The Attempt at a Solution Not exactly sure how to go about this...is it saying...
  19. P

    Time Period of SHM: Mass of System or Just Mass?

    Hi, I performed an experiment investigating the Time Period of oscillations. I wanted to know whether the m in the equation represents solely the mass hung on the spring or the mass of the system, that is, the mass hung plus the mass of the spring itself? Thanks
  20. R

    SHM: Which is amplitude and which is displacement?

    Homework Statement Calculate acceleration and velocity of a piston. Stroke is 150mm and engine speed 3500rpm Using simple harmonic motion equations Homework Equations a = -ω^2*s v = ω*√A^2 - s^2 ω = 2*∏*f v = velocity, a =...
  21. N

    Energy conservation vs momentum conservation in SHM

    Homework Statement a mass M , attached to a horizontal spring executes SHM(simple harmonic motion) with amplitude A1 . when the mass M passes through its mean position then a smaller mass m is placed over it and both of them move together with amplitude A2 . the ratio A1/A2 is ...
  22. P

    F = ma 2007 Exam - Question #25 - SHM with a box in water

    Homework Statement Find the period of small oscillations of a water pogo, which is a stick of mass m in the shape of a box (a rectangular parallelepiped.) The stick has a length L, a width w and a height h and is bobbing up and down in water of density ρ. Assume that the water pogo is...
  23. J

    Is the Acceleration of a Pendulum Zero at its Equilibrium Point in SHM?

    how does it make sense that in SHM the acceleration of a pendulum is 0 when it pases through its eqm point? surely as SHM is v. similar to circular motion (in terms of the maths) acceleration is constant? also, how can the force be MAX at eqm point?
  24. J

    How do you find time period of an oscillatory motion(not SHM)

    Homework Statement Force ( F ) = -kx /√( x^2 + r^2 ) where k is a constant and r(constant-amplitude) is the distance initially the object is away from the origin, x(variable) is distance of the object from the origin. Find time period of this oscillation 2. The attempt at a solution...
  25. I

    SHM: Choose Sin or Cos to Solve?

    I wanted to ask if weather I choose sin or cos makes difference in solving problems. In this question the answer is (a) but, what I am asking is that I got cos instead of sin ( from the general form X=Acos(ωt + ∅ )
  26. K

    Particle constrained by 4 springs SHM

    A point mass is constrained to move in the horizontal plane. It is attached to four fixed pegs by four light springs. The four pegs are arranged at the corners of a square of side a√2. Each spring has natural length a/2 and spring constant k. Show that the mass executes SHM with angular...
  27. V

    Does time period of SHM vary with frame(inertial and non inertial)?

    Does time period of SHM vary with frame(inertial and non inertial)?? Homework Statement There is an SHM. First observer is watching it from inertial frame of refrence and secodn is from non inertial will there any change of time period for both observer. Homework Equations just think...
  28. M

    What is the phase of the simple harmonic motion at t = 10.0 s?

    Homework Statement The function x = (2.0 m) cos[(6π rad/s)t + π/2 rad] gives the simple harmonic motion of a body. Find the following values at t = 10.0 s. I am having trouble finding the phase of the motion, The book gives an answer of 190 rad, I am not sure how they got that Homework...
  29. V

    Is the Motion of a Rubber Ball in a Concave Surface Simple Harmonic Motion?

    Homework Statement lets have a look on scene; there is a concave of radius R.(like concave lens) there is a rubber ball of radius r(r<<R). It is placed in equilibrium position in the concave. Now it is displaced by small distance along concave and released,friction is sufficient enough for...
  30. P

    What is the velocity of the block when it reaches the equilibrium position?

    Homework Statement This was a question on my 2nd midterm that I am still curious about. An unusual spring has a force law given by F = -cx^3 where x is in meters, F is in Newton's, and c has units of N/m^3. The spring is used to launch a 3.00 kg block across a horizontal frictionless...
  31. Z

    Eqn for SHM, sin function, so why cos?

    I had thought the eqn of simple harmonic motion is a sinusoidal function of time, with the eqn being: x(t) = A sin(wt + ∅0) Halfway down this page: http://electron9.phys.utk.edu/phys135d/modules/m9/oscillations.htm in Problems: in solution (a) it gives; The displacement as a...
  32. C

    How Do You Calculate the Period of SHM from a Cosine Function?

    Homework Statement A 2.30 kg mass on a spring has displacement as a function of time given by the equation x(t) = (7.40 cm)cos[(4.16)t-2.42] a) Find the time for one complete vibration. The back of the book had this same equation but a different mass, so I was able to figure out...
  33. S

    Exploring Negative Signs in SHM Equations

    Hi all, I know that there are many ways to derive the equations for SHM. I'm clear on how the negative signs come out when we use derivatives; but I've a problem understanding how the negative signs come into play using the reference circle. 1. If the centripetal acceleration is a = rω2...
  34. E

    Understanding the vmax = -wA Equation in Simple Harmonic Motion (SHM)

    Homework Statement A large mass bobs up and down on a heavy spring. Initially it is at the top. It achieves its maximum downward velocity of 94 cm s-1 in 0.25 s from its release. What are the period, angular freuqnecy, and amplitude for this motion? Find amplitude . Homework Equations...
  35. B

    Solving SHM: Max Speed & Accel. for 1.11kg Mass on Spring

    Homework Statement A mass of 1.11 kg on a spring rests on a frictionless surface and has a horizontal force of magnitude 1.23 N applied to it to keep it 1.3 m from the equilibrium. The mass undergoes simple harmonic motion when released. What is the maximum speed? What is the maximum...
  36. QuarkCharmer

    What Is the Tension in a String During Simple Harmonic Motion?

    Homework Statement a 0.12kg mass is suspended on a magic string with no mass, and length of 0.80m. There is no air resistance, and the pendulum is swinging such that it makes a maximum angle of 45 degrees with the vertical. A.) What's the speed as it passes the vertical position? B.) What is...
  37. 1

    Understanding the Phase Constant in Simple Harmonic Motion

    Homework Statement The displacement of a mass oscillating on a spring is given by x(t) = xmcos(ωt + ). If the initial displacement is zero and the initial velocity is in the negative x direction, then the phase constant is: Homework Equations The Attempt at a Solution How do I...
  38. A

    Time Period of SHM: Opposite Charges in Springs

    1. Homework Statement Two Springs are present (one just infront of the other). The Spring towards the left has +Q charge and towards the right -Q charge (at their ends).The distance between the two charges is d. The Springs are of length l. Find the Time Period of the Simple Harmonic Motion...
  39. A

    Time Period SHM of Two Springs with +Q & -Q Charges

    Homework Statement Two Springs are present (one just infront of the other). The Spring towards the left has +Q charge and towards the right -Q charge (at their ends).The distance between the two charges is d. The Springs are of length l. Find the Time Period of the Simple Harmonic Motion if...
  40. A

    SHM- Problem with negative signs

    I have problems understanding the use of negative signs in SHM. ie. mx''=-kx Why is there a negative sign for the constant k and what does the negative sign mean?
  41. F

    Problem with last step of SHM derivation

    Homework Statement A masss m ossilates on a spring, find the position as a function of time. Homework Equations F=ma F=-ky The Attempt at a Solution Well known problem, set m(dx/dt) = -kx get roots of characteristic equation and sub into general solution, x = Aexp(iwt)...
  42. C

    SHM question involving a tunnel through earth

    Homework Statement A tunnel is bored through the centre of the Earth from Liverpool to New Zealand and a travel pod is dropped into it. The gravitational force on the pod is proportional to its distance from the centre of the Earth and so it undergoes simple harmonic motion described by...
  43. J

    Solve SHM Problem: 1 Initial Condition

    What is the best way to go about solving a SHM problem that asks for amplitude and phase constant when only one initial condition (x(0)) is given? I'm a little confused because I read that to find A and the phase constant you must use the initial conditions - but I've encounter a few problems...
  44. jaumzaum

    Why Does Strumming Force Not Alter the Pitch of a Guitar String?

    Guitar strings behave like a spring when tuned: F = k.x is the tension in the string, where k is the contant of the string and x the displacement (when tuned). So by the equation : v = \sqrt{ F/u} where u is the linear density of the string. v = \lambda.f -> f...
  45. A

    Kinetic Energy relative to total energy in SHM

    Homework Statement (a) When the displacement in SHM is one-half the amplitude A, what fraction of the total energy is kinetic energy? What fraction is potential? The Attempt at a Solution I tried finding a ratio of KE/t, where t=KE+PE and PE/t but I got answers that didn't...
  46. A

    How Can I Calculate the Maximum Kinetic Energy of an Oscillating Object in SHM?

    Homework Statement I have a graph of position x plotted vs time t of an 18g object oscillating in SHM at the end of a spring. How can I find the objects maximum kinetic energy from that? The Attempt at a Solution It seems like i need to find the value of the spring constant k...
  47. J

    SHM Pendulum length/gravity question

    T= 2pie Square root of 2L/3g I got a couple of questions. 1) why is it 2L/3g? 2) would my straight line graph be T^2 vs L? ( so gradient is T^2/l?) 3) after i get my gradient do i compare it to the gravity 9.81? 4) is the equation going to be time^2=XXL or s^2=xxm ? do i use the unit...
  48. R

    Why is T = 1/f in Simple Harmonic Motion?

    An object undergoing simple harmonic motion will always have varying acceleration. That means for each unit of time passing by, different distances will be covered within the bounded amplitude. As an example suppose T= 10s. Therefore, f = 1/T = 0.1 Hz(1/10th of a wavelength). This in a way would...
  49. A

    Finding postion, velocity and accelration as functions of time (SHM)

    Homework Statement A 1.00-kg glider attached to a spring with a force constant 16.0 N/m oscillates on a frictionless, horizontal air track. At t = 0, the glider is released from rest at x = -2.50 cm (that is, the spring is compressed by 2.50 cm). Find the position, velocity, and...
  50. jaumzaum

    Why a spring-mass assembly is a SHM?

    I was trying to understand why a spring -mass assembly and a simple pendulum is a simple harmonic movement. I've done like this: In a SHM that starts in -A, we have x = -A.cos(wt) In a spring-mass we have that the maximum velocity is...
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