Energy, Work, and Power
Work, Power, Energy and Society are all components found in forms of movement that pertain to forces. Work refers to the force and direction of movement of a force, energy is the capacity to do work and power is the rate at which energy is transformed or the rate at which work is done. Most movements in basketball that involve a force can be expressed through work, power, and/or energy.
Energy can be found in either potential and/or kinetic form, however it can also be found as many different types. According to the Law of Conservation of Energy, energy cannot be created or destroyed, but can be transferred from one form into another. In basketball, common types of energy found in or used by players include: mechanical energy (potential/kinetic), gravitational energy (potential), thermal energy (potential/kinetic), sound energy (potential/kinetic), static electric energy (potential) and chemical energy (potential). Energy transformations can be expressed through energy transformation diagrams.
Energy can be found in either potential and/or kinetic form, however it can also be found as many different types. According to the Law of Conservation of Energy, energy cannot be created or destroyed, but can be transferred from one form into another. In basketball, common types of energy found in or used by players include: mechanical energy (potential/kinetic), gravitational energy (potential), thermal energy (potential/kinetic), sound energy (potential/kinetic), static electric energy (potential) and chemical energy (potential). Energy transformations can be expressed through energy transformation diagrams.
Energy, Work, and Power of a Pass
The video above shows the path of a ball being passed from one person to another. The girl passing the ball contracts her muscles, which means there is stored mechanical/gravitational potential energy in the ball that she is holding. When the girl extends her arms and snaps her wrist in order to send the ball forward to the receiver, she transfers that stored mechanical/gravitational potential energy in the ball into mechanical kinetic energy. When the ball reaches its maximum height, the ball comes to a stop (0 m/s at max. height). The kinetic mechanical energy it once had now transforms back into gravitational potential energy. Once the ball is past its maximum height it will rely on the force of gravity to bring it down into the receiver's hand. As it is moves downward, the gravitational potential energy transforms into mechanical kinetic energy. When the receiver catches the ball, the mechanical kinetic energy then transforms into sound energy, thermal energy (due to friction), and a small amount of static electric energy (also due to friction if passed back and forth enough) The energy transformation diagram below describes the transformation of energy from the ball’s maximum height until it lands.
The following calculations express the work, power, and energy used by the passer in order to pass the ball to the receiver.
Other Forms of Energy Transformation
Energy, work and power principles also apply to shooting a jump shot. The shooter on the ground starts with gravitational/mechanical potential energy. When he jumps up and moves the ball from his shooting pocket (start position) to his release point it transforms into mechanical/gravitational kinetic energy. At his maximum height, shooters tend to stay in the air for a split second with the ball at their release point, which is referred to as hang time. Scientifically, this means that the ball and boy have gravitational potential energy. When the ball is released it follows a similar energy transformation as the path of the pass (parabolic motion), except instead of a receiver, the net stops the motion of the ball. If the ball goes in the kinetic energy turns into sound, thermal, a small amount of static electric, and tension in the mesh of the net.
Dribbling also undergoes energy transformation, however its motion it follows one-dimensional vertical path in most cases (unless "crossing over" the ball). The ball has gravitational potential energy at the top of its path when it is not in motion (when the boy holds the ball). When a force is applied downward onto the ball, its gravitational potential energy transforms into kinetic energy until it hits the ground. The kinetic energy turns into sound, thermal, and static electric energy, until the force of the ball brings the ball back upwards into the boys hand. The upward path of the ball transforms the previous energy into kinetic energy once more until the hand catches it. When the hand catches the ball, it transforms kinetic energy into sound, thermal, and static electric. This motion is repeated every time someone dribbles, and each time the hand goes to apply a force on the ball more friction is created, thus created more thermal and static electric energy.