Acrobats perform stunts at height, and if the person is dangling to the right, the pole should be mo

The balance of the lever is only one reason, if the actor only relies on holding a counterweight in his hand to adjust the balance, why not use a shorter rod, why not use an iron ball, a weighing stone, but use such a long stalk, there is also the factor of inertia, the longer and heavier the rod, the greater the force required to make the rod turn, the actor walks on the wire, once he loses his balance, he immediately turns the long rod with both arms, so that he gets a force in the opposite direction, and returns to the center of gravity, once I saw a tightrope walking performance, the actor did not hold a long pole, but took a big banana fan, by fanning the air on the side of the body, using the air resistance to adjust their balance, the reason is the same, that fan has no counterweight.

If a person shakes to the right, it means that the right is heavy and the left is light, just like a scale, and if you want him to be flat, you must either reduce the weight on the right side or increase the weight on the left side. Moving the rod to the left is exactly to reduce the weight on the right side and increase the weight on the left side at the same time. to achieve balance.

It's the center of gravity, not the center.

The second floor is basically right.

But the rod and the person themselves are also a system, do not say separately.

When a person shakes to the right, the center of gravity is to the right, and when the rod is moved to the left, it is also to seek balance by turning the center of gravity to the left.

So if the person is dangling to the right, the rod should be shifted to the left.

to achieve equilibrium.

In fact, you have a misunderstanding, the reason why an actor can maintain balance is because his center is always directly above the tightrope, so maintaining balance and the center is directly above the tightrope is the same thing.

When the person is to the right, his own center of gravity is to the right, and the center of the rod to the left is moved to the left, so that their common center is offset by the left and right, which is equivalent to not moving, I hope you can understand.

When the person moves to the right, the center of gravity will be to the right, so it is necessary to move the pole to the left to return the center of gravity to the original equilibrium position.

The sum of two opposing forces is 0!That's why people can be balanced!

CA option Male can jump higher than female, so the mass can be smaller than female or Chun Thick.

Option B is the same as A, as long as the initial velocity is large enough.

C mechanical energy = mgh + 1 2mv "Shirt Town" female mgh, the woman went up.

d process has a positive force of resistance, no.

The maximum speed is good, and the difficulty is four meters per second.

The length is six meters. Principle: Because the force from 0 to 1 second is 180n, the downward acceleration is 120 divided by 30 to 4 meters per second.

And because of the decline, the friendship banquet thought for a second and then slowed down.

So the maximum speed is 4

And because the initial and final speeds are 0 and have a uniform variable speed.

So the average speed is 2 meters per second.

So the length is 6 meters per second.

1) Taking people as the research object, the force of gravity mg and the force f1 of the rod on the person during the acceleration of the descent of the human being, it can be seen from the title diagram that the force f1 of the rod on the man in the process of accelerating the sliding is 180 n from Newton's second law.

mg f1 = ma, then a = 4 m s2

When the velocity of the person reaches the maximum at the end of 1s, then v= at1=4 m s

2) The displacement during the acceleration descent is: =2 m, and the kinetic energy theorem is obtained when the deceleration descends the old nucleus.

Substituting data to solve the problem

So, the length of the bamboo pole

The maximum speed is four meters per second.

The length is six meters. Principle: Because the force from 0 to 1 second is 180N

Therefore, the downward acceleration is 120 divided by 30 to 4 meters per second, and then decelerates after one second of decline.

So the maximum speed is 4

And because the initial and final speeds are 0 and have a uniform variable speed.

So the average speed is 2 meters per second.

So the length is 6 meters per second.

Solution: (1) <>

The maximum value of the <> function is <>

A: The maximum height at which an actor can bounce is <>

Rice. 2) When x=4, <>

So this performance was a success.

When climbing upward, the hand has a tendency to move downward, so the static friction of the pole opponent is upward;

When sliding downward, the hand moves downward relative to the bar, so the sliding friction of the rod opponent goes up

Therefore, we choose: ac

The acrobat crawls upwards at a constant speed along the hard pole.

Constant velocity indicates that the force is balanced.

He is vertical, and is pulled by gravity and the rod, and these two forces are balanced and gravity is straight down, so vertical upward is the pulling force.

But how is the pull created? It is due to the hand pulling the rod, the rod gives him a reaction force, and this reaction force is generated by the frictional force of the rod on his hand.

Therefore, I should choose it as a person.

b d Actual Tension is classified by the effect of force, and friction is classified by the nature of force, so it is not good to mix together!

My point of view.