Dr. Ta-You Wu worked on Western scietific research during his early years and introduced physics to China. After having earned the honorary title of "The Father of Chinese Physics" and hand-picked two of his students to receive the Nobel Prize in Physics (the first two Chinese to do so), he collaborated with Dr. Hugh Ching in solving the problem of touch or collision without bouncing off, a problem missed by Isaac Newton, the Father of Western Physics, and all the scientists since Newton. The following is one of the first article introducing the new physics concept of jumpulse, and its Chinese translation in Dr. Wu's own handwriting.

The old tennis.com website under Chris Evert shows that jumpulse tennis is ten time more popular than any other post.

Summary of Proposal to National Science Foundation

Proposal Summary: Jumpulse and Law of Touch Demonstrated by Prolonged Contact between Ball and Racket during Collision

Click here for the full proposal
Click here for the References

This proposed research deals with the new physics concept of jumpulse, which denotes a sudden change of force, as impulse is a sudden change of momentum. This proposal will investigate prolonged contact due to a force, jumpulse, applied during a collision between a ball and a racket. In order to have two objects moving together, they need to have the same position, velocity, and acceleration. Sometime during the impact, the velocity and the position of the ball and the racket are the same and, if then the acceleration is suddenly increased, prolonged contact can be achieved. Prolonged contact leads to the Law of Touch, which states, unlike velocity, acceleration can be changed instantaneously. Prolonged contact is directly related to touch because a robot finger bounces off a surface like a ball bounces off a racket, and touch can be defined as permanently prolonged contact at low impact velocity. Table below shows clearly that jumpulse is a missing concept central to the description of motion (for robot touch).

Table Terminology and Concept in Describing Motion

Velocity; Acceleration; Jerk (ISO); Snap (?); Crack (?); Pop (?)

Momentum; Force;Yank (?);Tug (?); Snatch (?); Shake (?)

Energy; Energy of Acceleration

Impulse; Jumpulse(?)

Some definitive Yes or No questions regarding prolonged contact serve to focus the goal of the proposal:

(1) Does prolonged contact exist?

(2) If prolonged contact exists, how to achieve prolonged contact?

(3) Can acceleration or force be increased instantaneously by a finite amount?

(4) Is the above concept of an instantaneous change of force missing in the description of motion?

The feasibility of prolonged contact has been demonstrated in an experiment, where two colliding cars, which can represent the ball and the racket, moving together after the collision, as shown in the video: http://www.youtube.com/watch?v=PixwnjvNlNQ. Jumpulse can be defined below with infinite d3x/dt3:

.......... Jumpulse = {Integral of} d3x/dt3 dt, where (t2- t1) approaches and can equal zero
...................... t1 to t2

Instruction on How To Double-Hit a Tennis or Ping Pong Ball

1. Drop the ball on the table or ground to let it bounce up to about chest high.
2. Move the racket quickly vertically (perpendicular to the ground) very close to the ball, but not touching.
3. Touch the ball with small impact velocity.
4. As soon as the racket touches the ball, increase the acceleration of the racket as much as possible.
5. Your swing of the vertically held racket should end up as far back behind your shoulder as possible.
[Note: The entire stroke should be consisted of one smooth swing. Double-hitting became legal in tennis in 1982 and in table tennis in 2004.]

This research project will take one year and will be carried out based on the extensive preliminary study of the phenomenon of touch. Ultraslow motion videos for 3 seconds will be produced with 7000+ fps and 32 GB of memory to study the effect of a force applied during the 4-millisecond impact of a collision.

Intellectual Merit: Jumpulse is a step function of force vs. time. Jumpulse and the Law of Touch are missing central concepts in the description of motion necessary in prolonged contact in tennis and touch.

Broad Impact: Learning prolonged contact in sports based on jumpulse should be exciting to most students around the world. Textbooks on mechanics and sports should include the concept of jumpulse. The proposal will challenge physicists world-wide to think physically the solution of prolonged contact. Key Words: jumpulse; robot touch; dynamic contact; applied force; collision; impulse; prolonged contact.

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The instruction book for coaches of professional players and possibly the longest tennis.com thread (Click Here)

Juan Martín del Potro Two-Handed Jumpulse Backhand Stroke (Click Here)

(Click Here)

The web site devoted to showing double-hitting: (Click Here)

Relationship to golf: (Click Here)

Dr. Ta-You Wu, Father of Chinese Physics, coined the word jumpulse in his paper: (Click Here)

In Russia: (Click Here)

Opinions: (Click Here)

Video: (Click Here)