**Aether Huang, Jay Butera**

**IB Physic**

4.1.1 - Describe examples of oscillation.

Pendulum, tuning fork, alternating current, mass on spring, earthquake, heartbeat.

4.1.2 - Define the term displacement,

amplitude, frequency, period, and difference.

4.1.3 - Define simple harmonic motion

and state the defining equation as a = -w2x.

Definition - Motion that takes place when the acceleration of an object is proportional to its displacement from its equilibrium position and directed towards its equilibrium position.

6.3.4 Determine the direction of the

force on a charge moving in a magnetic field.

6.3.2 Draw magnetic field

patterns due to currents.

6.3.1 State that moving charges

give rise to magnetic fields.

**Kinematics of Simple Harmonic Motion**

Examples:

Displacement

Distance in a particular of a particle

from its mean position.

Definition:

Amplitude

The maximum displacement from equilibrium position.

Definition:

Frequency

The number of cycles that the pendulum makes per unit time.

Definition:

Period

The time taken for one complete cycle.

Definition:

Difference

Difference in phase between the particles of two oscillating system, measured in radians.

Definition:

Defining Equation - a = -w2x

1. Acceleration is in opposite direction of displacement.

2. Directed back towards the equilibrium position.

4.1.4 - Solve problems using

defining equation for SHM

6.3.3 Determine the direction of the force on

a current-carrying conductor in a magnetic field.

**Simple Harmonic Motion**

**Energy changes during simple harmonic motion (SHM)**

4.2.1 Describe the interchange between kinetic energy and potential energy during SHM.

4.2.3 Solve problems, both graphically and by calculation, involving energy changes during SHM.

4.1.6 Solve problems, both graphically and by calculation, for acceleration, velocity, and displacement during SHM.

**Magnetic force and field**

6.3.5 Define the magnitude

and direction of a magnetic field.

**Magnetic force and field**

Magnetic fields is caused by the movement of electric charges, therefore current will produce a magnetic field.

Sample question 1

A mass on a spring oscillates with simple harmonic motion of time period 2.5s. At its maximum displacement it is 5m away from its equilibrium position. Find the maximum acceleration.

W= 2(pi)/T = 2(pi)/22.5s = 2.5s-1

a = X(W)^2=(5m)(2.5s-1)2=32ms2

The kinetic and potential energy vary proportionally with a constant total energy.

◦

1 = cos^2(theta) + sin^2(theta)

A mass m on a spring oscillates in SHM. Express the total energy in the system algebraically at each of the three points shown in the picture located in the note.

b) PE = 12kx^2 = 12kXo^2 KE = 12mv2 =12m(0)2 = 0

a) PE = 12kx^2 = 12k(0) KE = 12mv2 =12mvo2

c) Equivalent to (b)

- Maximum displacement

xo=amplitude=1000m

- Velocity at 7.50s

vo=wxo

v = vocos(t) => v=wxocos(wt)

=(2(pi)/20.00s)(1000m) cos(2(pi)/20.00s7.5s) = -220ms-1

- Acceleration at 7.50s

ao= wvo

= (-2(pi)/20.00s)(-220ms-1)sin(2(pi)/20.00s(7.50s))

= 48.9ms-2

Using the right hand rule, the force is perpendicular to the magnetic field and the current.

The force is perpendicular to the direction of the magnetic field, and the moving charge. If the moving charge is parallel to the magnetic field, then there is no acting force.

*Correspond with the Graph in the note.

The magnetic field is perpendicular to the force and current.

B = Fb/q|v|sin(theta)

A good sum up of the material we went over