Physics experts come in, help

To use a simple analogy, there is a small ball that is connected to your hand by a rope, and now you are asked to use just the right amount of force to turn the ball in the horizontal plane.

Then you first increase the speed of the ball, and you can obviously feel that the tension of the rope has become larger, that is, the train is exerting force outward, pressing the outer rails; Returning to that just right state, if you reduce the speed of the ball, it will not be able to continue to maintain a horizontal motion, which is equivalent to the train pressing the inner side of the rails.

PS: I was going to explain it to you with a formula graphic, but unfortunately I can't use a map

Does this kind of question still need to be answered by a master?

The wheels of the train are erected between the inner and outer rails, when the speed is too large, the centrifugal force is greater than the centripetal force, and the pressure will be applied to the outer rail, when the speed is small, vice versa.

The problem of centrifugal force pulls.

According to the formula f ma

a is equal to centripetal acceleration pull, and the centrifugal force can be expressed by this formula.

The w in the middle of f m r w w represents the angular velocity, which should be changed to the linear velocity v.

f＝m＊v＊v／r

R is the turning radius, thank you, I have described it very specifically, the reason for this is the reason for inertia, because speed is a vector, when the direction of speed changes, the action of external force is required, I am a professional physicist, hehe, thank you

Generally speaking, the outer track of the train is higher than the inner track, and this is also a problem on the road

When the speed is less than V, because the track is one high and one low, under the action of gravity, the inner side will be under pressure, so generally speaking, the train should limit the speed when passing the curve

Also, this question is a very simple basic question, and high school textbooks should have these

Adversity. This is still very difficult to say, you have to draw a force analysis diagram, and you can also calculate that the limit value of this speed is 2 gh l under the root number

This train track is drawn out below a slope with a bit of an inclination, alas, in short, it is not very clear without a picture.

This kind of problem, our teachers have talked about it, you should talk about it too, read the notes.

Did you get your question wrong? [Slide the right end of the board to the left and slide the plank] There seems to be a problem here.

The principle of solving this problem is:

1》Conservation of mechanical energy, that is to say, the two physical energy potential energy and kinetic energy involved here are equal to the initial kinetic energy, that is, 1 2mv2=1 2m(1 2v)2+1 2mv'2, plus the law of conservation of momentum mv=1 2mv+mv'Forming a system of binary linear equations can be used to find the mass ratio.

2》Maximum kinetic energy: The velocity of the board and the iron block is the same when the maximum kinetic energy is the same, that is, the application of the law of conservation of momentum, that is, mv1=(m+m)v2, at this time, v2 can be obtained, and the kinetic energy is found by the kinetic energy formula.

This question hurts, (the first ten seconds) the speed of the motorcycle reached 20, 100 meters, the speed of the bus is still 30, 300 meters; The motorcycle traveled another 20 t distance, and the passenger car traveled 30- 1 2 x t 2 ; Finally, using the distance off series equation, the total distance traveled before and after the motorcycle is equal to the total distance traveled by the car plus 300 meters. The end result is a quadratic equation about t, which you can solve yourself. The above solution is not difficult to solve the second question.

I haven't used my pen for many years, and the equation won't be solved, alas, it fell).

1. Calculate the time taken by the car to stop t1 and the distance traveled s1.

t1=10+（0-30）/（-1）=40ss1=10*30+30*30-1/2*1*30^2=300+450=750m

At this time, the car stopped, and the starting point from Lao Li to start chasing the car was: 300 + 750 = 1050m (second question answer: 1050m).

2. The motorcycle can only catch up with the car after running 1050 meters, and the time it takes is: t2 = uniform acceleration time + uniform speed time = (20-0) 2 + (1050 - the distance of the acceleration stage s2) 20 = 10 + (1050-1 2 * 2 * 10 2) 20 = 10 + The first question answer: