power and speed

[tensai]

I am confused about the relationship between power and speed.
I thought that power and speed are the same thing, because when someone hits the ball hard, the ball has pace and it is heavy. Is this true? If it isn't, how can you hit a slow, but powerful shot, or vice versa.
Any answers will be appreciated

[Rickson]

Coria has a lot of speed, but not a lot of power.

[tensai]

How is that possible?

[jun]

I am not sure what you really mean here.
If the ball is traveling fast, then it's pretty powerful shot. Sometimes, tennis players will talk about heaviness of the ball, which results in combination of power and spin.

Someone could have quick hands, but could be not the most powerful players. It could be due to size (body weight), or just nature of the stroke.

[tensai]

Sorry if I'm not saying this clearly.
What I want to know is the relationship between the power and speed of a shot.
If a shot travels fast, then is the shot always powerful?
Then, can I interpret that a ball that is traveling fast is powerful, and a ball is traveling slow, is not powerful?
I really don't understand what a "powerful" shot is.

[wt888usa]

well if there's a lot of top spin (heavy ball), the ball will start out slowly, and then drop very fast and kick back up very fast. i thnk that would be considered fast, but when you see it, it doesn't seem like a "powerful" shot, just that the spin is really adding a lot of speed to it? just a guess, :P

[Bungalo Bill]

I think Jun said it correctly.

I think a ball can be traveling fast as each player uses the pace of the ball to hit it back. But at some point a player will add power or force the ball to move faster. This explosion is what I would refer to as power.

The spin on the ball can on top of this make the ball heavier. The tighter or more revolutions the ball has with the speed it is traveling it becomes "heavier" on the strings.

The power (energy) of the ball is physically defined by the mass, the speed and the spin, since the ball can have the (bulk) kinetic energy and rotational energy. As to the speed, we can resolve it into vertical and horizontal velocity. Both speed and spin vary due to gravity, air friction and bounce.

When a ball is hit from point A, bounce at point B and reach at point C, there are two trajectories- before and after the bounce. There are infinite paths to reach point C by different combinations of initial velocity (horizontal and vertical), project angle (which affects B or no bounce point) and spin (topspin, underpin or flat).

A fast ball can mean how long the time the ball reach at C, so even same initial speed, a flat ball bounces at same B, there are two profiles before the bounce, high profile takes longer time. For example, a sky-high defensive lob is a fast moving but slow and powerless shot.

How powerful the ball is, is defined by the horizontal velocity, the spin and the hitting point of the racquet when receiving the ball. Owing to the friction between the ball and the racquet, a torque created on the racquet if the ball spins. A topspin shot makes the ball heavier vertically. Normally, after bouncing, the ball acquires topspin. It is because of the friction between the ball and the court surface. However, it is possible to make the ball without any spin after bounce by the underspin . Moreover, an underspin makes the ball float on the flight. Since both the ball and the stringbed of the racquet are not rigid body, the horizontal kinetic energy can be stored and released by the racquet. Moreover, if the player hits at the center of percussion (the sweet spot), reaction force at the rotation axis vanishes. The receiver won't feel horizontal power of the ball. Therefore, when a moderate underspin, high horizontal velocity ball is hit at the sweet spot, it is not powerful. An backhand slice approach is not a powerful shot but it is a difficult shot because it bounces low.
What is a powerful but low pace shot? When a low ball is hit at the center mid-court and aimed at the y corner. Heavy topspin and low speed has to be applied to ensure the ball inside the court and over the net.
What is a powerful and high pace shot? A heavy topspin, high horizontal velocity, small net clearance deep down-the-line shot!

[Camilio Pascual]

Originally Posted by Salad

However, it is possible to make the ball without any spin after bounce by the underspin.

And it is also possible for the ball to have underspin after the bounce.

[Datacipher]

Originally Posted by Camilio Pascual

And it is also possible for the ball to have underspin after the bounce.

That would not happen during any conventional groundstrokes, serves or volleys. Would only happen on trick and specialty shots.

[Camilio Pascual]

K-rect. Such as anything that hops back over the net.

[Datacipher]

Originally Posted by Camilio Pascual

K-rect. Such as anything that hops back over the net.

Fair enough, that is what I assumed you must be referring to...