What is the relationship between the tension of a tennis racket and the ball played with this racket

If the tension of the line is lower (the line bed is loose), the ball is more powerful, but the ball control is relatively weakened, and on the contrary, the ball power is reduced and the ball control is improved.

However, beginners generally aim to be able to hit the ball smoothly, and it is recommended to have a lower tension rate.

In addition, the racket with a narrow and thin frame generally needs to exert more force on its own, which must have smooth movements and a good sense of the ball to use it, on the contrary, the racket with a wide and thick frame can generally assist in the force, that is, even if the action is not perfect enough and the hitting point is not accurate enough, it will also play a better return (in terms of strength, but the royal road is always its own smooth action).

Federer, 50-55

Nadal, 53

Ljubicic, 57

Roddick, 73

Davydenko, 53-55

Ansic, 55-57

Hewitt, 56

Ferrero, 51-53

Robredo, 51

Henman, 52 and the fact that in the past, the Sampras could wear more than 70 pounds, and now most people are still 50 60.

The power of the ball should still be most related to individual skill. Purely from the equipment, the string bed is looser, the racket is harder, and the power of the ball will be greater. Because the ball is wrapped in the bed of string for a longer period of time.

The thread is loose and elastic because it takes a long time to contact the ball.

Since the action of the force is mutual, when the hand slaps the ball hard, the hand will be subjected to the reaction force of the ball circle, so the hand feels pain, and the force object at this time is the ball, and the force object is the hand orange ruined

Therefore, the answer is: the history of the ball; Hand; Ball; Hand;

a. The tensile force of an ant is much smaller than 1n, which is not in line with the topic;

B. The gravity of a bag of instant noodles is about 1N, and the gravity of two eggs is about the same, which is about 1N.

c. The area of the mouth of the can is 25cm2

Left and right, the pressure of the atmospheric nuclear trap is 105

Around PA, the force to open the ruler of the can is f=ps=105pa=

About 25n does not fit the topic;

d. The force of the tennis racket hitting the ball is larger, and it is about dozens of bulls, which does not meet the meaning of the topic, so choose B

Hitting the ball with a racket, the racket gives the ball a round remorse, if the ball is the object of research, then the object of force is the racket

Since the action of force is reciprocal, and at the same time, the ball will also give a reaction force to the racket If the racket is taken as the object of study, then the object to which the force is applied is the ball

Therefore, choose B

After checking the literature for so many years and reading Internet posts for so many years, I have never seen a table tennis batting racket force analysis diagram. The author tried to make an answer sheet, and I implore all golfers, heroes, sports biomechanics experts, medical professors, physics teachers, and scholars.

The batting force is equal to the speed of the racket (and the speed of the incoming ball), and the speed of the racket is to gravity, the force of the human muscles, and the ground support reaction (the ground support force consists of the upward ground support force (elastic force) and the horizontal friction force).

The human body is abstracted into a multi-rigid body model (Fig. 1), and the limb links are semi-rigid and semi-flexible links between the joints, and the soles of the feet are constrained by horizontal rough planes. The limbs of the whole body exert their strength independently in a certain order. Among them, it is common to hold the racket hand to drive the racket, the torso to drive the arm, and the lower limb to drive the whole body.

According to Newton's first law of motion, any change in the state of motion of an object (such as acceleration, velocity, displacement, momentum, rotation, etc.) is determined by the resultant external force. Therefore, when drawing a force diagram of the human body, it is not necessary to draw both internal forces (such as the interaction force between limbs) and external forces of the human body (such as the force of pushing the ground). Because the forces in the human body will cancel each other out, the resultant force (moment) is zero, and the object of the ground kicking force is the ground.

For rackets, both the gravitational force of the racket and the force transmitted by the hand holding the racket are external forces; For the human body, the human gravity force and the ground support reaction force (elastic force, friction force) are both external forces.

1 Horizontal swing power.

In Figure 1, looking at the soles of the feet, the ground support reaction force F2 caused by the kicking force F1 (not shown in the figure) consists of the elastic force Fn and the forward horizontal friction force Fh. fn balances with gravity g at the center of gravity of the human body, i.e., the resultant external force in the up-down direction is zero. Obviously, when the racket is swung horizontally forward, the downward gravity is completely canceled out by the upward spring.

At this time, the three external forces are only left with the forward friction force fh, which is the direct ** of the horizontal acceleration swing force.

2 Diagonal upward acceleration swing force.

In Figure 2, when the racket is swung forward and upward, it is clear that the combined force in the up-and-down direction is greater than zero (fn g), i.e., after the downward gravitational force g is completely counteracted by the upward elastic force fn, there is still a residual elastic force (white line at the center of gravity). At this time, only the forward friction force fh and the upward part of the elastic force are left, and the two are combined into the swing force f3.