Answer:
When two unequal forces act in opposite directions on an object, the net force is the difference of the two forces. In the example below, the net force would be 50 Newtons (500 - 450 = 50), and the object would move to the left because the force pulling to the left is greater.
Answer:
The total distance the bird travels is d.
Explanation:
Each train travels at the speed s. They will meet at the center, a distance d/2 (which is where the bird might be crushed). Each train travels the same distance d/2 in a time t which is also equal for both. This is also the time the bird spends travelling between them.
For any of the train, the time t is the distance divided by the speed.
![t = \dfrac{d/2}{s} = \dfrac{d}{2s}](https://tex.z-dn.net/?f=t%20%3D%20%5Cdfrac%7Bd%2F2%7D%7Bs%7D%20%3D%20%5Cdfrac%7Bd%7D%7B2s%7D)
The bird travels at the speed of 2s. Its distance is given by the product of its speed and the time taken.
![d_\text{Bird} = \dfrac{d}{2s}\times 2s = d](https://tex.z-dn.net/?f=d_%5Ctext%7BBird%7D%20%3D%20%5Cdfrac%7Bd%7D%7B2s%7D%5Ctimes%202s%20%3D%20d)
Answer:
please read the answer below
Explanation:
To find the electric field you can consider the Gaussian law for a cylindrical surface inside the slab.
![\int E dA=EA_{G}=\frac{Q_{int}}{\epsilon_o}](https://tex.z-dn.net/?f=%5Cint%20E%20dA%3DEA_%7BG%7D%3D%5Cfrac%7BQ_%7Bint%7D%7D%7B%5Cepsilon_o%7D)
![Q_{int}=\rho V_{G}](https://tex.z-dn.net/?f=Q_%7Bint%7D%3D%5Crho%20V_%7BG%7D)
where Qint is the charge inside the Gaussian surface, AG is the area of the surface and rho is the charge density of the slab.
By using the formula for the volume of a cylinder you obtain:
![V_{G}=\pi r^2h](https://tex.z-dn.net/?f=V_%7BG%7D%3D%5Cpi%20r%5E2h)
where h is the height. If you assume that the slab is in the interval (-zo<z<z0) you can write VG:
![V_{G}=\pi r^2 z](https://tex.z-dn.net/?f=V_%7BG%7D%3D%5Cpi%20r%5E2%20z)
Finally, by replacing in the expression for E you get:
![E=\frac{Q_{int}}{\epsilon_o A_G}=\frac{Q_{int}}{\epsilon_o \pi r^2}\frac{z}{z}=\frac{\rho z}{\epsilon_o}](https://tex.z-dn.net/?f=E%3D%5Cfrac%7BQ_%7Bint%7D%7D%7B%5Cepsilon_o%20A_G%7D%3D%5Cfrac%7BQ_%7Bint%7D%7D%7B%5Cepsilon_o%20%5Cpi%20r%5E2%7D%5Cfrac%7Bz%7D%7Bz%7D%3D%5Cfrac%7B%5Crho%20z%7D%7B%5Cepsilon_o%7D)
![E=\rho z/\epsilon_o](https://tex.z-dn.net/?f=E%3D%5Crho%20z%2F%5Cepsilon_o)
hence, for z>0 you obtain E=pz/eo > 0
for z<0 -> E=pz/eo < 0
Not at all. Density on its own is not sufficient