Can you know which ball is bad

The correct answer is (1) take 8 from 12, 4 to 4, if balanced, then take 2 from the remaining 4, 1 to 1, if balanced again, then take 1 from the remaining 2 and the normal one, such as the second unbalanced, then any of the 2 unbalanced and normal one can be called.

2) If the first time is unbalanced, then we temporarily call the first heavy end of the heavy ball, the light end is called the light ball, now, the 2 heavy balls and 1 light ball are matched, 3 to 3 weighed, such as balance, then the remaining 2 of any one and the normal one is on the line. If it is not balanced, then it is normal to judge that it is normal to have 1 light ball at the heavy end and 2 heavy balls at the light end, and now there are only 2 heavy balls and 1 light ball left.

Divided into four groups, 1, 2, 3, 4.

The first time it is called 1,2, the balance is 3,4, otherwise it is 1,2.

The second time, you might as well set it in 1,2, and 1 sink, take 2 balls in 1 and add a good ball to the left end of the scale, take 1 ball in 2 and add 2 good balls to the right end, balance the bad ball in 1 and the remaining 2 in 2, otherwise in 1 out of 2 and 2 out of one.

The third time, you might as well set the bad ball in 1 out of the two and 2 out of one, at this time is the key, call one of the two, if balanced, then 2 out of the light, if not balanced, 2 out of the normal, so 1 out of the two one of the two heavier than the other (the second time has been determined 1 sinking), the answer has been obtained, the unbalanced sinking is the bad ball!

First divided into four groups: 1, 2, 3, 4.

1) Weigh 1,2 first, balance at 3,4, otherwise at 1,2.

2) Set in 1,2, and 1 sink, take 2 balls in 1 and add a good ball to the left end of the scale, take 1 ball in 2 and add 2 good balls to the right end, balance the bad ball in 1 and 2 in the remaining 2, otherwise in 1 out of 2 and 2 out of one.

3) Set the bad ball in the two of 1 and 2 out of one, this is the key, call one of the two, if balanced, then 2 out of the light, if not balanced, 2 out of the normal, so 1 out of the two one of the two heavier than the other (the second time has been determined to sink 1), unbalanced then sink the one is the bad ball.

1。Take 10 scales first, put five on one side, if the same, take the other two, if not.

2。Take out one of the light five, and the other four, two on each side, if the same is the one that was taken out, if it is different.

3。Take out the light two, one on each side.

That's it, satisfied.

...Even the ones that are memorized are also in the first year of junior high school science homework.

Let's read it on my homework during the winter vacation of elementary school

Distinguishing the quality of basketball is mainly from the following aspects:

1。Liner, of course, you can't cut the basketball to see inside, but you can try its bounce soft and stable by slapping the basketball, and the basketball with a good liner puts the ball on the chest and falls vertically, and the height of each ** is the same.

2。Yarn wrapping, good yarn wrapping can make the bouncing of the basketball textured, the ball flight and rotation are stable and accurate when shooting, and it will make the ball firm and not easy to deform. The judging method is to press the basketball repeatedly with both hands, if it feels solid and rebounds strongly, it proves that the yarn is better.

3。Epidermis, a good epidermis should have the advantages of anti-slip, wear-resistant, sweat-absorbing, etc., and the test of anti-slip can directly feel whether the ball has a feeling of touching your hands. For the abrasion resistance test, you can use your fingernails to scrape the surface of the basketball, if there are obvious scratches, the epidermis is less abrasion resistant.

As for sweat absorption, wipe the surface of the basketball with a damp cloth, if it becomes dry sooner, it proves that sweat absorption is better.

4。Feel, feel this thing is not very easy to say, experts can feel good or bad in the hand, if you don't have experience in this area, please pay more attention to compare the weight of the basketball, and whether the texture is standardized, consistent.

A good ball means that the weight of the ball is within the specified quality range, and such a ball has strong rotation, easy control, and straight line, on the contrary, it is an unqualified ball, the weight is not enough, the thickness is uneven, and the depth of the depression of the shot is different. The ball should not be controlled and should not be played in a straight line. If you use a bad ball for a long time, you won't be able to play when you use it well.

Good balls are comfortable to play, bad balls affect mood.