lady gaga in the house- just dance

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Slam Dunk Science

Physicist Teaches Basic Science Principles To Help Basketball Players Make Their Shots Every Time

Basketball players looking to rule the court may need more than just skill and endurance to be a top player. A good dribble, some fancy footwork ... It might look good on the court, but when it comes to playing the game, getting the ball through the hoop is what basketball is all about.

But it'’s not that easy for every player. Now, physicist and former college ball player, John Fontanella, teaches a few basic principles of science to help players make the basket every time!

One popular move is the jump shot. But many players release the ball too soon and miss the basket.

“"One of the most important things that I found ... is that the ball really needs to be released right at the top of the jump,"” Fontanella said.

At that moment, the player isn't moving -- his velocity is zero. Releasing the ball at the top gives the player better control of the ball and making it more likely that he will make the shot. Another shot, the lay-up, can be an easy shot to make by hitting the backboard at just the right spot.

“"I found the sweet spot for a right-hand lay-up and the sweet spot for a left-hand lay-up,”" Fontanella said.

The secret is hitting the top corners of the square on the backboard; the angle of the ball is perfect and lands the shot almost every time.

“"A little bit of knowledge of physics helps you play the game better,”" Fontanella said.

The American Association of Physics Teachers contributed to the information contained in the TV portion of this report.

BACKGROUND: Good basketball players develop their skills through endless repetition, hard-wiring the brain with the correct sequence of muscle movements for optimal play (“kinesthetic memory”). However, knowing a little basic physics can still help you improve your game. You can learn why you should put a spin on the ball, get tips on improving your free throws, and discover the secret to Michael Jordan'’s seemingly longer “hang time.”

PUTTING A SPIN ON IT: Once the basketball leaves the shooter’'s hand, it travels in an unchanging parabolic path that can be calculated using Newton’'s laws of motion. But putting a backspin on the ball can help you make more free throws. When a spinning ball bounces, it bounces back in the direction of the spin. If the ball hits the backboard or back of the rim, it will be directed toward into the basket. That’'s because when the ball makes contact with the rim or backboard, the backspin causes a change in velocity opposite to the spin direction, making it more likely that the ball will drop into the net softly.

HANG TIME: Michael Jordan earned the nickname “Air Jordan” because of his seemingly longer “hang time” making jump shots in games, but this is an illusion. How high someone can jump depends on the force used to push on the floor when starting to jump, which in turn depends on the strength and power of the jumper’s leg muscles. The harder and more powerful the jump, the higher and longer the flight. In order to leap four feet into the air, the hang time would be 1.0 seconds. Jordan had a few tricks up his sleeve to make that hang time seem longer. When he dunked, he held onto the ball a bit longer than most players, and actually placed it in the basket on the way down. He also pulled his legs up as the jump progressed so it appeared that he was jumping higher. But it still all happened in less than one second.

Article Source : www.sciencedaily.com

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Physics Of Gymnastics

All body movements in the sport of gymnastics like the somersault, twist and handstand are all related with the physics of gymnastics.

Torque

Every time a gymnast does a twist or somersault on the floor, the gymnast usually performs a back handspring or a round off to achieve more speed for its execution. The force produced and the lever-like movement in twists and somersaults is called torque. More torque means more number of twists or somersaults that can be performed by the gymnast in a series or movements. Torque, in general, plays a big role in gymnastics physics in terms of rotational movements.

Somersaults

Horizontal Force: In the physics of gymnastics, horizontal force is the most common method used in initiating a somersault. This force is usually applied to the feet. Gymnasts basically throw their bodies to perform a twist or somersault and to do this, they need to gain momentum when they throw both arms and head backwards and up.

Vertical Force: A gymnast can also do a somersault by applying vertical forces to the feet. Using this force in the physics of gymnastics can allow a gymnast to do a somersault by throwing the upper body. Vertical force produces torque by leaning forward or backward before leaping.

Somersault without Torque: A gymnast can also perform a somersault without torque. However, only a limited amount of body rotation will be achieved. A torque-free somersault can be performed by a gymnast by keeping the legs as well as the body straight and by rotating the arms by the shoulders backwards. This will cause the gymnast’s body to tilt backwards making a somersault.

Twists

Twist with Torque: Basically, a torque twist is done by standing on a hard surface and then pushing the feet off the ground. Anyone can twist his or her body in 180 degrees by applying force to the feet and pushing off the floor. Same with somersaults, a gymnast can easily control force that initiates the rotation by throwing the arms in the twist’s direction before the feet leave the ground.

Twist without Torque using Angular Momentum: Momentum is also involved in the physics of gymnastics. Twists do not need torque but momentum. Assume a gymnast performing a somersault and is currently in a twisting position. His body possesses a great amount of angular momentum from the left axis to the right. This is the reason why his body is not touching the ground.

Twist without Torque and Angular Movement: This type of twist is usually referred to as the “cat twist”. Gymnasts that use the right techniques can perform body rotations without torque or rotations using head to toe axis. Just like a cat that is thrown in the air that can perform different motions before landing on the ground.

Handstands

A handstand is the most basic skill in the sport of gymnastics. If you become an expert in the handstand, other skills will follow. To do the handstand one must be able to hold the body in a “tight” position and like all other gymnastics skills it is executed in a straight line. If the line is not maintained then control will be lost.

The force of gravity is against the gymnast when performing a handstand. To avoid falling, the center of gravity must be directly applied over the hands. In addition, your back and hips should be kept straight so that gravity will not pull you down.

As a whole, the handstand is best represented by the concept of center of gravity. This skill is very hard because it is difficult to keep the center of gravity perpendicular to the ground.

Gymnastics and physics are always associated with each other. Gymnastics is a sport very exciting to watch because of different body movements. And in every movement, the physics of gymnastics is connected.


Source : www.tuckandroll.net

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How the Physics of Football Works- Part 2

Runners on the Field

When we look at runners on the field, several aspects can be considered:

• Where they line up for a play
• Changing directions
• Running in an open field

Line-Up Positions
When we look at the positions of the backs, both offensive and defensive, we see that they typically line up away from the line of scrimmage on either side of the offensive and defensive linemen. Their positioning allows them room, or time, to accelerate from a state of rest and reach a high speed, to either run with the ball or pursue the ball carrier. Notice that the linebackers have far more room to accelerate than the linemen, and the wide receivers have far more room than the linebackers. So linebackers can reach higher speeds than linemen, and wide receivers can reach the highest speeds of all.

Changing Directions on the Field
Let's look at an example of a running play in which the quarterback hands the ball off to a running back. First, the running back starts from the set position, at rest, and accelerates to full speed (22 mi/h or 9.8 m/s) in 2 s after receiving the ball. His acceleration (a) is:

• a = (v_f - v_o)/(t_f - t_o)
  • v_f is final velocity
  • v_o is initial velocity
  • t_f is final time
  • t_o is initial time
• a=(9.8 m/s - 0 m/s)/(2 s - 0 s)
• a= 4.9 m/s²

As he runs with the flow of the play (e.g. to the right), he maintains constant speed (a = 0). When he sees an opening in the line, he plants his foot to stop his motion to the right, changes direction and accelerates upfield into the open. By planting his foot, he applies force to the turf. The force he applies to the turf helps to accomplish two things:

• Stop his motion to the right
• Accelerate him upfield

To stop his motion to the right, two forces work together. First, there is the force that he himself applies to the turf when he plants his foot. The second force is the friction between his foot and the turf. Friction is an extremely important factor in runners changing direction. If you have ever seen a football game played in the rain, you have seen what happens to runners when there is little friction to utilize. The following is what happens when a runner tries to change his direction of motion on a wet surface:

1. As he plants his foot to slow his motion, the coefficient of friction between the turf and him is reduced by the water on the surface.
2. The reduced coefficient of friction decreases the frictional force.
3. The decreased frictional force makes it harder for him to stop motion his to the right.
4. The runner loses his footing and falls.

The applied force and the frictional force together must stop the motion to the right. Let's assume that he stops in 0.5 s. His acceleration must be:

• a = (0 m/s - 9.8 m/s)/(0.5 s - 0 s)
• a = -19.6 m/s²
  *The negative sign indicates that the runner is accelerating is in the opposite direction, to the left.

The force (F) required to stop him is the product of his mass (m), estimated at 98 kg (220 lbs), and his acceleration:

• F = ma = (98 kg)(-19.6 m/s²) = 1921 Newtons (N)
• 4.4 N = 1 lb
• F = ~500 lbs!

To accelerate upfield, he pushes against the turf and the turf applies an equal and opposite force on him, thereby propelling him upfield. This is an example of Isaac Newton's third law of motion, which states that "for every action there is an equal, but opposite reaction." Again, if he accelerates to full speed in 0.5 s, then the turf applies 1921 N, or about 500 lbs, of force. If no one opposes his motion upfield, he will reach and maintain maximum speed until he either scores or is tackled.

Running in an Open Field
When running in an open field, the player can reach his maximum momentum. Because momentum is the product of mass and velocity, it is possible for players of different masses to have the same momentum. For example, our running back would have the following momentum (p):

• p = mv = (98 kg)(9.8 m/s) = 960 kg-m/s

For a 125 kg (275 lb) lineman to have the same momentum, he would have to move with a speed of 7.7 m/s. Momentum is important for stopping (tackling, blocking) runners on the field.

Blocking and Tackling

Tackling and blocking runners relies on three important principles of physics:

• Impulse
• Conservation of momentum
• Rotational motion

Photo courtesy North Carolina State University
Players use physics to stop each other on the football field.

When Runner and Tackler Meet
When our running back is moving in the open field, he has a momentum of 960 kg-m/s. To stop him -- change his momentum -- a tackler must apply an impulse in the opposite direction. Impulse is the product of the applied force and the time over which that force is applied. Because impulse is a product like momentum, the same impulse can be applied if one varies either the force of impact or the time of contact. If a defensive back wanted to tackle our running back, he would have to apply an impulse of 960 kg-m/s. If the tackle occurred in 0.5 s, the force applied would be:

• F = impulse/t = (960 kg-m/s)/(0.5 s) = 1921 N = 423 lb

Alternatively, if the defensive back increased the time in contact with the running back, he could use less force to stop him.

In any collision or tackle in which there is no force other than that created by the collision itself, the total momentum of those involved must be the same before and after the collision -- this is the conservation of momentum. Let's look at three cases:

1. The ball carrier has the same momentum as the tackler.
2. The ball carrier has more momentum than the tackler.
3. The ball carrier has less momentum than the tackler.

For the discussion, we will consider an elastic collision, in which the players do not remain in contact after they collide.

1. If the ball carrier and tackler have equal momentum, the forward momentum of the ball carrier is exactly matched by the backward momentum of the tackler. The motion of the two will stop at the point of contact.

2. If the ball carrier has more momentum than the tackler, he will knock the tackler back with a momentum that is equal to the difference between the two players, and will likely break the tackle. After breaking the tackle, the ball carrier will accelerate.

3. If the ball carrier has less momentum than the tackler, he will be knocked backwards with a momentum equal to the difference between the two players.

In many instances, tacklers try to hold on to the ball carrier, and the two may travel together. In these inelastic collisions, the general reactions would be the same as those above; however, in cases 2 and 3, the speeds at which the combined players would move forward or backward would be reduced. This reduction in speed is due to the fact that the difference in momentum is now distributed over the combined mass of the two players, instead of the mass of the one player with the lesser momentum.

The Tackling Process
Coaches often tell their players to tackle a runner low. In this way, the runner's feet will be rotated in the air in the direction of the tackle. Let's look at this closely:

Tackling a runner low requires less force because the tackler is farther away from the runner's center of mass.

Imagine that the runner's mass is concentrated in a point called the center of mass. In men, the center of mass is located at or slightly above the navel; women tend to have their center of mass below their navels, closer to their hips. All bodies will rotate easiest about their center of mass. So, if a force is applied on either side of the center of mass, the object will rotate. This rotational force is called torque, and is the product of the amount of force applied and the distance from the center of mass at which the force applied. Because torque is a product, the same torque can be applied to an object at different distances from the center of mass by changing the amount of force applied: Less force is required farther out from the center of mass than closer in. So, by tackling a runner low -- far from the center of mass -- it takes less force to tackle him than if he were tackled high. Furthermore, if a runner is hit exactly at his center of mass, he will not rotate, but instead will be driven in the direction of the tackle.

A lineman crouches low so that his center of mass is closer to the ground. This makes it hard for an opposing player to move him.

Similarly, coaches often advise linemen to stay low. This brings their center of mass closer to the ground, so an opposing player, no matter how low he goes, can only contact them near their center of mass. This makes it difficult for an opposing player to move them, as they will not rotate upon contact. This technique is critical for a defensive lineman in defending his own goal in the "red" zone, the last 10 yards before the goal line.

­

We have only touched on some of the applications of physics as they relate to football. Remember, this knowledge appears to be instinctive; Most often, players and coaches don't consciously translate the mechanics of physics into their playing of the sport. But by making that translation, we can understand and appreciate even more just how amazing some of the physical feats on the football field really are. Also, applying physics to football leads to better and safer equipment, affects the rules of the sport, improves athletic performance, and enhances our connection to the game.

Source : entertainment.howstuffworks.com

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How the Physics of Football Works- Part 1

When you throw a football across the yard to your friend, you are using physics. You make adjustments for all the factors, such as distance, wind and the weight of the ball. The farther away your friend is, the harder you have to throw the ball, or the steeper the angle of your throw. This adjustment is done in your head, and it's physics -- you just don't call it that because it comes so naturally.

Football Image Gallery

Photo courtesy San Francisco 49ers Fred Beasley of the 49ers running the ball. See more football pictures.

Physics is the branch of science that deals with the physical world. The branch of physics that is most relevant to football is mechanics, the study of motion and its causes. We will look at three broad categories of motion as they apply to the game:

• Delivery of a football through the air
• Runners on the field
• Stopping runners on the field

Watching a weekend football game could be teaching you something other than who threw the most passes or gained the most yards. Football provides some great examples of the basic concepts of physics -- it's present in the flight of the ball, the motion of the players and the force of the tackles. In this article, we'll look at how physics applies to the game of football.

Throwing the Football

When the football travels through the air, it always follows a curved, or parabolic, path because the movement of the ball in the vertical direction is influenced by the force of gravity. As the ball travels up, gravity slows it down until it stops briefly at its peak height; the ball then comes down, and gravity accelerates it until it hits the ground. This is the path of any object that is launched or thrown (football, arrow, ballistic missile) and is called projectile motion. To learn about projectile motion as it applies to football, let's examine a punt (Figure 1). When a punter kicks a football, he can control three factors:

• The velocity or speed at which the ball leaves his foot
• The angle of the kick
• The rotation of the football

The rotation of the ball -- spiral or end-over-end -- will influence how the ball slows down in flight, because the ball is affected by air drag. A spiraling kick will have less air drag, will not slow down as much and will be able to stay in the air longer and go farther than an end-over-end kick. The velocity of the ball and the angle of the kick are the major factors that determine:

• How long the ball will remain in the air (hang-time)
• How high the ball will go
• How far the ball will go

The angle of a kick helps determine how far it will travel.

When the ball leaves the punter's foot, it is moving with a given , velocity (speed plus angle of direction) depending upon the force with which he kicks the ball. The ball moves in two directions, horizontally and vertically. Because the ball was launched at an angle, the velocity is divided into two pieces: a horizontal component and a vertical component. How fast the ball goes in the horizontal direction and how fast the ball goes in the vertical direction depend upon the angle of the kick. If the ball is kicked at a steep angle, then it will have more velocity in the vertical direction than in the horizontal direction -- the ball will go high, have a long hang-time, but travel a short distance. But if the ball is kicked at a shallow angle, it will have more velocity in the horizontal direction than in the vertical direction -- the ball will not go very high, will have a short hang-time, but will travel a far distance. The punter must decide on the best angle in view of his field position. These same factors influence a pass or field goal. However, a field goal kicker has a more difficult job because the ball often reaches its peak height before it reaches the uprights.

Football by the Numbers Since physics is a quantitative science, developing some units and measures is a good way to begin to understand the effects of physics on football. Consider these useful numbers and units developed by Dr. David Haase of North Carolina State University:

• Player at full speed - ~22 miles per hour (9.8 m/s)
• Linebacker - ~220 pounds (98 kg)
• Offensive lineman - ~300 pounds (133 kg)

Source : entertainment.howstuffworks.com

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Biomechanics & Physics of Sport

Biomechanics is the sport science field that applies the laws of mechanics and physics to human performance, in order to gain a greater understanding of performance in athletic events through modeling, simulation and measurement. It is also necessary to have a good understanding of the application of physics to sport, as physical principles such as motion, resistance, momentum and friction play a part in most sporting events.

Biomechanics is a diverse interdisciplinary field, with branches in Zoology, Botany, Physical Anthropology, Orthopedics, Bioengineering and Human Performance. The general role of Biomechanics is to understand the mechanical cause-effect relationships that determine the motions of living organisms. In relation to sport, Biomechanics contributes to the description, explanation, and prediction of the mechanical aspects of human exercise, sport and play.

Source : www.topendsports.com

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The Powerful of Quantum Pendant

Have you ever heard about quantum locket? or ever seen it previously?

This is some video related to the locket. Either you believe it or not, THAT'S ARE YOUR CHOICE!!! Enjoy to watch.





Some info about Quantum Pendant

Quantum Pendant is made from natural minerals that are fused and structurally bonded together at molecule level. It produce the scalar energy that helps to enhance the body's spiritual. It also help to maintain energy balance in our body so that our bodies maintain health and well being.

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Why dark at night?

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Rotator Cuff

The Rotator Cuff is a very important part of the functional shoulder. It consist of four muscles: supraspinatus, infraspinatus, teres minor and subscapularis. These group serves as abductors, lateral rotators and medial rotators of the shoulder. They also act as depressors of the humerus. This function keeps the action of deltoid from pulling the head of humerus upward into the subacromial space, which would cause impingement of the cuff.

Impingement is caused when subacromial space, area between the top of the humerus and the bottom of acromion becomes closed off and pinches the ratator cuff. Symptoms include pain, weakness and loss of motion. Movements above the shoulder tend to increase pain. Pain while sleeping is often encountered. Beside the weakness of rotator cuff, impingement can be caused by abnormal acromions.

Impingement syndrome may be classified in three stages.

Stage one is usually associated with an overuse injury by someone who is under the age of 25. The rotator cuff is weakened, but the condition is often reversible.

Stage two usually involves people from the ages of 25 to 40, and the condition is more advanced, with some irreversible tendon damage beginning to arise.

Stage three is the result of years of build up, and often involves tendon rupture or tear. This is seen mostly in patients over the age of 50.

Understanding the impingement syndrome is aided by understanding the physical properties of the tendons, which make up the cuff. The strength and stiffness of tendons, which give them their mechanical advantages, comes from collagen molecules.

Collagen molecules run parallel to each other and derive their characteristic strength from the cross-linkage between them. New collagen has relatively few cross-links, but as it matures, the number of cross-links grows, therefore increasing the strength and stiffness of the fiber. This maturation process begins to level off with age however.

For old patients, the number of stable cross-links being formed drops off considerably, therefore reducing the strength of the tendon. Tendon strength is also affected by the demand placed on it. Compared to young patient which is often reversible because of the properties of the tendons.

Treatment is rather conservative, consisting of rest and ice, followed by a strengthening program and possibly some physical therapy.

An active person who exercises frequently will have much stronger tendons than an inactive person will. Disuse or immobilization of tendons causes them to weaken considerably, as no demands are being placed on them.

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Physics Principle & Application

Co-relation PHYSICS principle and body system - application

Cardiac Cycle

Pressure is defined as force per unit area and is measured in pascals [Pa = N/m2]. The term pressure is used when describing fluids (gases or liquids). If a fluid is at rest, pressure is transmitted equally to all its parts and, at any one point, is the same in all directions.

Pressure plays an important role in our health, as for example blood pressure in the human circulatory system.

Blood pressure is the pressure that is exerted by blood against the walls of the arteries as it travels through the body. When the volume of blood pumped through the arteries or the pressure that the blood puts against the walls of the arteries increases, the delicate tissues in the artery walls wear thin and may tear.

Fat and cholesterol deposits further obstruct blood flow, narrowing the arteries, and thereby accelerating damage by raising blood pressure even more. Elevated blood pressure speeds up the progress of atherosclerosis, and wears out the coronary arteries faster than normal. High blood pressure may cause heart failure, kidney failure, and strokes.

As blood travels through the arterial system, the heart contracts and relaxes. When blood pressure is measured, two values are given. The first, called the systolic pressure, refers to the pressure on the arterial walls when the heart contracts and the second, called the diastolic pressure, is the measure of the pressure when the heart relaxes.

For adults normal blood pressure is less than 19 kPa systolic, and 12 kPa diastolic. Blood pressure above this value is considered unhealthy and should be treated.

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Physics Field - introduction

First of all i want to share some information about what is meant by physics and the application of physics in our daily life.

Physics Definition
~a natural science that concern with all aspects of nature.
~the general analysis of nature, conducted in order to understand how the world and universe behave.
~covering the behavior of objects, origin of gravitational, electromagnetism, and nuclear force fields.




Physics covers a wide range of phenomena, from the smallest sub-atomic particles (protons, neutrons and electrons), to the largest galaxies.

The aims is to describe the various phenomena that occur in nature in terms of simpler phenomena. Thus, physics aims to both connect the things we see around us to root causes, and then to try to connect these causes together in the hope of finding an ultimate reason for why nature is as it is.



Advantage:
advances in the understanding of electromagnetism or nuclear physics led directly to development of new products which have dramatically transformed modern-day society (e.g., television, computers, domestic appliances, and nuclear weapons); advances in thermodynamics led to the development of motorized transport; and advances in mechanics inspired the development of calculus.


I would share more PHYSICS FIELD info s to you all in the next post. TQ




~BEYOND THE FIELD~

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