# Harmonic motion

What is the frequency of this oscillation? Solution Substitute 0. According to Newton's second law, the net force must therefore be zero. The stiffer the spring is, the smaller the period T. It is important to remember that when using these equations, your calculator must be in radians mode.

## Simple harmonic motion pendulum

The position can be modeled as a periodic function, such as a cosine or sine function. The more massive the system is, the longer the period. A description of each position is as follows. The weight is constant and the force of the spring changes as the length of the spring changes. In fact, any regularly repetitive motion and any wave, no matter how complicated its form, can be treated as the sum of a series of simple harmonic motions or waves, a discovery first published in by the French mathematician Baron Jean-Baptiste-Joseph Fourier. The object oscillates around the equilibrium position, and the net force on the object is equal to the force provided by the spring. What is so significant about SHM? Therefore, the mass continues past the equilibrium position, compressing the spring. Note that the positive direction is typically chosen to be the direction that the spring is stretched.

We define periodic motion to be any motion that repeats itself at regular time intervals, such as exhibited by the guitar string or by a child swinging on a swing. Figure 2 shows five critical points as the mass on a spring goes through a complete cycle. What is so significant about SHM? For the object on the spring, the units of amplitude and displacement are meters.

### Simple harmonic motion graphs

Example Simple harmonic motion is characterized by this changing acceleration that always is directed toward the equilibrium position and is proportional to the displacement from the equilibrium position. The maximum of the cosine function is one, so it is necessary to multiply the cosine function by the amplitude A. The force is also shown as a vector. Consider the block on a spring on a frictionless surface. The velocity is the time derivative of the position, which is the slope at a point on the graph of position versus time. See the free-body diagram in Figure 6 below. The other end of the spring is anchored to the wall. This is done for the case of the oscillating spring-mass system in the table below and the three functions are shown in Figure 3. What is so significant about SHM? Thus simple harmonic motion is a type of periodic motion. In this case, there is no normal force, and the net effect of the force of gravity is to change the equilibrium position. It helps to use Newton's second law, which tells us that a negative maximum acceleration occurs when the net force is negative maximum, a positive maximum acceleration occurs when the net force is positive maximum and the acceleration is zero when the net force is zero. The more massive the system is, the longer the period.

See the free-body diagram in Figure 6 below. A related quantity is the frequency f, which is the number of vibrations the system makes per unit of time.

## Simple harmonic motion khan academy

Two forces act on the block: the weight and the force of the spring. The greater the mass of the object is, the greater the period T. In some form, therefore, simple harmonic motion is at the heart of timekeeping. The stiffer the spring, the shorter the period. At the equilibrium position, the net force is zero. The string vibrates around an equilibrium position, and one oscillation is completed when the string starts from the initial position, travels to one of the extreme positions, then to the other extreme position, and returns to its initial position. The weight is constant and the force of the spring changes as the length of the spring changes. See the free-body diagram in Figure 6 below. The object oscillates around the equilibrium position, and the net force on the object is equal to the force provided by the spring. In fact, the mass m and the force constant k are the only factors that affect the period and frequency of SHM. According to Newton's second law, the net force must therefore be zero. The only two forces that act perpendicular to the surface are the weight and the normal force, which have equal magnitudes and opposite directions, and thus sum to zero.

In this section, we study the basic characteristics of oscillations and their mathematical description.

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