Energy

Sound energy:  
           Sound energy travel through media, such as gas liquid or solid, the energy produced by sound vibrations.

Thermal energy:
           In the other word is heat. The sum of potential energy and kinetic energy, in random motion of particles of a material.

Gravitational potential energy is energy an object possesses because of its position in a gravitational field. The most common use of gravitational potential energy is for an object near the surface of the Earth where the gravitational acceleration can be assumed to be constant at about 9.8 m/s²

. Elastic energy is the potential mechanical energy stored in the configuration of a material or physical system as work is performed to distort its volume or shape.

mechanical energy describes the sum of potential energy and kinetic energy present in the components of a mechanical system. Mechanical energy is the energy associated with the motion or position of an object.

Chemical potential energy：

Chemical potential energy is a form of potential energy related to the structural arrangement of atoms or molecules.

cannon

 A cannon works very similar to a gun works. A charge is loaded into the cannon (such as gunpowder) and then the cannonball is loaded in on top of the charge. Wadding is placed into the top of the cannon along with the fuse. The fuse is lit which sets the wadding on fire which in turn ignites the charge. The gases from the charge will rapidly expand causing the cannon ball to fly from the end of the cannon.

Equilibrium

• no friction
• a=0.....ax=0   ay=0

Inclines (Static)

• fs=mFN
• a=0
• +in direction of a
•  no air resistance
• m=tan(angle)

Inclines (Kinetic)

• fk=mFN
• +in direction of a
•  no air resistance
• ay=0

Pulleyès

• frictionless palleys trope
• no air resistance
• multiple FBD
• + in direction of a
• T1=T2
• a of system is the same

Trainès

• 1FBD for 2
• 3FBD for T1,T2
• ay=0
• a is resistant
• no air resistance
• + in direction of a

Eq#3     d = V1Δt + 1/2aΔt^2

we can know from the groph:

aΔt = V2-V1

Δabc----d2 = V1 Δt

Raceo-----d1 =1/2 (V2-V1) Δt

d = d1 + d2

    =V1 Δt + 1/2 (V2-V1) Δt

    =V1 Δt + 1/2 (aΔt) Δt

    =V1 Δt + 1/2aΔt^2

Eq#4   d= V2 Δt – ½ a Δt^2

we can know from the graph:

Δabd------d1 = (V1+V1) Δt

Rbdoe----d2 = V2Δt

d = V2Δt - (V1+ V2) Δt  

   = V2Δt - ½ a Δt^2

THE MOTOR REPORT

The materials we used to build the motor are: wood, nail(four long, four short), cork(cylinder), stack(axed), paper clips, thumbtacks(pin), pop can, and sand paper.

First we placed the four inch nails. The length between each two nails on the both side is two to three cm, and the space between each pairs is five to six cm. we hammered the nails onto the wood. Then we places pin through the centre of the cork. On the one end of the cork we placed two pins, they are the commutators. Then we warp the wire around the cork. We bare both ends of the wire and wrap the bared section around both of the pins. We cut the pop can into two pieces, hammered them into wood on the both side of the commutators pin. We also sanded both side of the pop can pieces, we used it as the brushes. put he magnets on the nails, with opposite facing each other.(1)

When connect with the power, the motor turned round 360 degrees, more than three times.

If there are on brushes the motor can’t turn three times, it will stop. The current must be swish. The two brushes are used to swish the current. Without the brushes, if one of the wires goes to the top, the motor will be stopped, because the magnetic field on the wire are going two different ways. With the brushes helping swish current, so the magnetic field on the wire can also be swished. So the motor can be turn around more than three times.

From the project, team work and organization is very important. A good team work and organize effect on the result good or not. To do the better work also depend on the prepare work.

Right hand rule:

• For conventional current flow grasp the conductor with the thumb of the right hand pointing in the direction  of  conventional or positive, current flow. The curved fingers point in the direction of the magnetic field around the conductor.

• Grasp the conductor with the right hand such that curved fingers point in the direction  of  conventional or positive, current flow. The thumb points in the direction of the magnetic field within the coil. Outside the coil, the thumb represents the north end of the electromagnet produced by coil.

Magnetic

• A magnetic field is the distribution of a magnetic force in the region of a magnet.
• As with electric fields, there are two different magnetic characteristics, labelled north and south.
• Metals like iron, nickel, and cobalt, or mixtures of these three are called the ferromagnetic metals.
• Earth acts like a giant permanent magnet, producing its own magnetic field.
• Lifting electromagnet, relay, electric bell are the uses of electromagnets.
• Similar magnetic poles, north and north or south and south, repel one another with a force at a distance.
• Dissimilar poles, north and south, attract one another with a force at a distance.
• Oersted's principle: charge moving through a conductor produces a circular magnetic field around the conductor.

Right hand rule:

• For conventional current flow grasp the conductor with the thumb of the right hand pointing in the direction  of  conventional or positive, current flow. The curved fingers point in the direction of the magnetic field around the conductor.
• Grasp the conductor with the right hand such that curved fingers point in the direction  of  conventional or positive, current flow. The thumb points in the direction of the magnetic field within the coil. Outside the coil, the thumb represents the north end of the electromagnet produced by coil.