Does anyone know about physics, and thank you very much for the random number D

Not so long ago, I saw you again.

The roar and clouds of different distances and nears.

He is also seriously irresponsible for his parents and all the relatives who care about him.

We don't live in this world for ourselves alone.

Ah, those familiar footprints.

Let the known time be t and the half-life be t

Then n is left with n original *(1 2) (t t)1 8=(1 2) (t t).

Get t t t 3

It can be seen that if the answer is d, then the time in the known condition should be days.

If you count it as 114 days, the result is 38 days (no answer optional), of course, your calculation process is fine, but the question is wrong.

The answer options for the question are incorrect.

Hello, I guess it was a typographical error, or the decimal point was omitted during the scanning of the web page, 114 should be, this particle in the title is obviously radon 222.

There is no displacement in the direction of the work done.

The extra kinetic energy is the gravitational potential energy transformation.

My understanding is that at the A side, the total resistance is the smallest, and the maximum current is 12 10=

At the B terminal, the total resistance is maximum, and the minimum current is 12 (50+10)=

So the answer is d

C or D, depending on the resistance value of the A and B terminals of the sliding rheostat.

Oh, m=r f, where denotes the cross product, and the magnitude m=iriifisin, however, it can also be done, 4i 3i=0, 4i 5j=20k, -3j 3i=9k, -3j 5j=0. Add up to 29k

Well, to explain, in the spatial Cartesian coordinate system, i j=k, j k=i, k i=j, if the above factors swap positions, the result should be added with a negative sign. For example, j i=-k.

To add, the moment is a directional quantity, and the multiplication used by m=r f is not a point product but a cross product, so the obtained quantity is still a directional quantity, and m is perpendicular to the plane where r and f are located.

Moment m=rx (vector cross product) f=4*5-(-3)*5=29It is oriented vertically and upwards with the paper side up.

with the same momentum.

To add, the answer on the first floor is that the kinetic energy is the same, and the electric potential in the initial and final states is the same, that is, the amount of change in kinetic energy is the same, but the initial kinetic energy is not necessarily the same, because the mass is not necessarily the same, so the kinetic energy in the final state is not necessarily the same.

c Here the kinetic energy and the electric potential energy are converted into each other, and the electric potential in the initial and final states is the same, so the kinetic energy must be the same, which is obtained according to the kinetic energy theorem.

It is known that f push = 100n, which is decomposed into horizontal and vertical forces, because the wooden box advances at a constant speed, and the horizontal force is balanced.

1) f friction = (g wood + f push sin37) = f push cos37 solution = 4 23

2) f push cos37 - g wood - f push sin37) = ma solution to get the acceleration a approx. =

I can't see the question clearly, how can I answer it?

What time did you start? I didn't learn any of that.