Vector Kinematics -Kinematics is the branch of mechanics concerned with the motion of objects without reference to the forces that cause the motion. Projectile Motion The path taken by a projectile is parabolic and mirrored about a vertical line that passes through the highest point of the flight. Vector A vector is a quantity that contains both magnitude and direction. Arrows can be used to represent vectors because the direction of the arrow gives the direction of the vector and the length of the arrow is proportional to the magnitude of the vector. A person leaves home and goes for a walk. He walks 40m east and 30m north. As a result, his vector displacement is 50m northeast. Dynamics the branch of mechanics concerned with the motion of bodies under the action of forces. Friction Friction is the resistance that one surface or object encounters when moving over another. The static frictional force can be found using Fs= µFN, where µ is the coefficient of static friton and FN is the normal force. Newton's second law of motion When a net external force acts on an object of mass, m, the acceleration, a, is directly proportional to the net force and has a magnitude that is inversely proportional to the mass.

Fnet=ma If a person is pushing a 1000 kg car at 0.05m/s^2, ignore the friction, the force reuqired to push the car will be 1000kg x 0.05m/s^2= 50N Work Work is an activity involving a force and movement in the direction of the force.

W=Fd where F is the magnitude of the force and d is the magnitude of the displacement. Energy Energy is the property of an object that allows it to produce change in environment or in itself. It is also the capacity for doing work. Momentum Momentum is a measure of how difficult it is to stop an object that is moving.

p=mv Circular Motion An Object that moves in a circle at a constanct speed, v, is said to experience uniform circular motion. Power Power is the amount of work done per unit time or the rate at which work is done. Gravitation Gravitation is the gravity, which abstracts object to each other. Electrostatics The study of stationary electric charges or fields as opposed to electric current. Electric Circuit A flow of electric charges through the electric conductor Electromagnetism The interatction of electric currents or fields and magnetic field.

Electromagnetic is the boss of all forces. Equilibrium A condition that sum of the force is equal to zero. When you are walking forward and push the floor back, the floor produces a friction force, which is greater than you applied force. Thus, you walk forward. Everyday, the windmail changes the wind energy into electric energy. Total before = total after On a balance scale, if two objects are motionless and balance at a same horizontal level, they have same weight, distance and force applied on both side. A baby with a momentum of 5kg-m/sec has a mass of 2.5kg. With what velocity is the child moving? When two electric fields cover together, they generate electricty. Ferris Wheels is moving in constant speed in circular motion. A man needs 980 J work to hold up a 50kg barbell to 2 m height.

W=Fd

W=mg x d

W=(9.8m/s^2)(50kg)(2m)

W=980 J There are Newton's Three Laws of Motion. When a bcylist rides and flies acroos the sky at 5 m/s at a height of 5m above the ground, the path it travelled in the air can be modelled by the projectile motion. Since kinematics is the study of motion and dynamics is the study of force, there with be no force if there is no motion. At the same time, if there is a force, there must be motion involving in it. When the sum of force is equal to zero, equilbrium occurs.

Torque = F·D Work is the product of the force and distance over which the force is applied The rate at which momentum changes with time is equal to the nect force applied to an object Total energy before = total energy after When a woman touches the top of the van de graaff generator, the van de graaff generator will attract all the protron from her hair to its bottom. As a result, her hair will become negative and go spicky because they are repeling each other. F=QvB where F is electromagnetic force, Q is charge, v is the velocity and B is the magnetic field.

The magnetic field is perpendicular to the electric field and vice versa. Total momentum before = toal momentum after When you pull the drain-plug, the water in bathtub will drain off becasue Earth's gravity is pulling and attracting the water towards its center. Planets in Solar System is attracted by the gravitational force of the Sun. Objects in circular path requries the knowledge of circular motion. The Millikan Oil Drop Experiment Moving electron to generate electric field Energy can be used to do work and work can be used to transfer energy Power is the total work done in a given time Power is the rate of energy used or released in a given time P=W·d Work= changing energy Physics 12 Physics is a natural philosophy and a natural science that involves the study of matter and its motion through space and time, along with related concepts such as energy and force Ohm's law It is a law stating that electic current is proportional to voltage and inversely proportional to resistance. V=IR, where V is the voltage of the battery, I is the current and R is the resistor. If there is a 5V battery and 5Ω resistor in a circuit, the current will be:

V=IR

I=V/R

I=(5V)/(5Ω)

I=1A p=mv

v=p/m

v=5kg-m/sec /2.5kg

v=2m/s Friction is a force that acts to resist the relative motion between two rough surfaces which are in contact. Fnet = Fc

Fc= mv2/r

When object is in circular motion, it reuqires centripetal force We can use the Ohm's law to firgure out the current, voltage or resistor in a circuit. Conservation Law When you turn on an electric heater, electrical energy is converted to heat energy. If you measure the amounts of electricity supplied to the heater and the amount of heat produced by the heater, you will find these amounts are equal. In order words, energy is conserved. They can be both conserved. Newton's first law: Every object persists in its state of rest or uniform motion in a straight line unless it is compelled to change that state by force impressed on it. This law can also be called as Law of Inertia. Newton's second Law of Motion: The relationship between an object's mass m, its acceleration a, and the applied force F is F=ma. Newton's third Law of Motion: For every action, there is an equal and opposite force. One of the Newton's Laws of Motion. When the roller coaster is at the top of a drop and not moving, there is no/low kinetic energy being used, but as the roller coaster plunges down a hill, kinetic energy increases as the speed of the coaster increases. After the battery send out the electric energy, the energy will then pass through all the resistors and finally come back to the battery. This process will keep going continously until the battery run out of electric energy. Magnetic flux Magnetic flux is the product of the average magnetic field times the perpendicular area that it penetrates.

Magnetic Flux= B A, where B is the magnetic field and A is the area which magnetic field passes through. A magnetic field of flux denstity 20 T passes down through a coil of wire. The coil has 10m length and 5m width. The magnetic flux though the flux will be :

magnetic flux= B A

= 20 T x (10m · 5m)

= 1000Wb Robert Millikan, one of the scientist determined that there was a smallest "unit" charge, used the Oil Drop Experienment to figure out the charge on electron by calculating the force of gravity on one drop and measuring the mass of one drop. As a result, he could then determine the charge that one drop must have. He noticed that the charge was always a multiple of -1.6 x 10^-19 C, the charge on a single electron. Both gravitation and electromagnetism are fundamental force. Flux is the componet of eletromagnetic field lines perpendicular to the area. The flux is often defined by the dot product of the field and the surface's unit normal vector. Electromagnetic force = BIl, where B is magnetic field, I is current and l is length

Elecromagnetism is the force that casues the interation between electrical charged particles and is responsible for pratically all the phenomena obesrved in daily life. Total momentum before = toal momentum after

Total energy before = total energy after I = Q/t, where I is the current, Q is the charge and t is the time.

Electric circuit, which is the electric current in a wire is often defined as the net amount of charge that passses through it per unit time at any point. Electromagnetic waves carry energy and momentum.

Fc = Fnet

Fnet=F

mv^2/r = QvB

mv = QBr P=VI

The rate at which electric energy is transformed by an electric circuit is defined as the electric power. Fc = F

mv^2/r = QvB

r = mv/QB

where Q is the charge of a particle, B is the magnetic field, r is the radius, m is the mass, and v is the velocity.

Since the force is F=QvB in a constant magnetic field, charged particle in a magnetic field feels a constant magnitude, which always directed perpendicular to its motion. This result is a circular orbit. . Kirchhoff's Law Two laws concerning electric networks in which steady currents are flowing. Junction Law: at any junction, the sum of all currents enetering the junction must equal the sum of all currents leavng the junction. Loop Law: the sum of the changes in potential around any closed path of a circuit must be zero. I= I 1 + I 2 Going around the blue loop, the voltage will drop across the resistor R , and then increased back to V as it is going back to the + sign of the battery. Same to red loop. Kirchhoff's Law is really helpful when it applies to find the current, resistor and voltage. F=Gmm/r^2 Newton's Law of Universal Gravitation

Every particle in the universe attracts every other particle with a force that is proportional to the product of their masses and inversely proportional to the square of the distance between them. This force acts along the line joing the two particles.

Earth has a force of gravity of 9.8m/s^2 An object fired into the air moves in a vertical, two dimensional plane. Velocity and acceleation are examples of vector because they have directions and magnitude. A quantity/motion which has magnitude and direction is a vector. Motion, which is fired in the air will experince in a parabolic route. This is called projectile motion. Since like charges repel and opposite charges repel, electric force is proportional to the product of the charges and inversely proportional to the square of the distance between them. F=kQQ/r^2

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# Universe! Physics

Mind map of Physics 12