The boyfriend had an argument while helping the girl to unscrew the bottle cap. What are the tips for unscrewing the bottle cap?

Because twisting a bottle cap is like peeling a banana and is not included in the nine-year compulsory education, most students have been using inefficient methods. First, let’s take a look at how you all twist this bottle cap:

Less efficient method:

Use the flexor pollicis longus tendon, the first dorsal interosseous muscle and the base of the index finger Use the side of the bone to hold the bottle cap. (Just say that the tiger's mouth will kill you, right?) The friction and force of this grip are not optimal.

In terms of friction, the side of the index finger bone is flat and cannot bend with the bottle cap, and the contact surface is not good enough. Moreover, scratching the two fingers on the side (just say the thumb and index finger will kill you, right?) cannot use the muscles of the forearm to hold it tightly, and the grip strength is very limited.

In terms of exerting force, this posture is only suitable for exerting force on the wrist. Use the wrist flexor muscles to bend the wrist inward and drive the bottle cap to rotate. According to this twisting method, given the development of girls' forearms, it is normal for tighter bottles to be difficult to unscrew. Those who can unscrew are all men.

More efficient method:

Hold the bottle body with your left hand, bend the thumb and ring finger of your right hand to grasp the bottle cap, keep your wrist straight, and your forearm only plays a gripping role . Use the biceps on both sides of your upper arms to work together to drive the bottle to move in your direction. The force of the entire system ultimately falls on the cap-bottle rotation axis.

The harder you use your right hand, the tighter it becomes: Use your right hand to hold the bottle cap, and with the help of your forearm, you can firmly hold the bottle cap in your hand.

In terms of friction, the inside of the ring finger can be close to the bottle cap, and when the four fingers are clenched, the strength of the forearm can be used.

In terms of force generation, remember to keep the wrist joints straight and push in the direction of the body. The strong force of the upper arms on both sides (relatively speaking) will be exerted on the bottle cap-bottle body rotation axis, forcing The cap unscrews from the bottle. Even girls can open bottle caps that boys can’t!