The movement of electric charge
depending on the object the force pressing in on the object are equal with the quantity of the object.
Answer:
a
The focal length of the lens in water is 
b
The focal length of the mirror in water is 
Explanation:
From the question we are told that
The index of refraction of the lens material = 
The index of refraction of the medium surrounding the lens = 
The lens maker's formula is mathematically represented as
![\frac{1}{f} = (n -1) [\frac{1}{R_1} - \frac{1}{R_2} ]](https://tex.z-dn.net/?f=%5Cfrac%7B1%7D%7Bf%7D%20%3D%20%28n%20-1%29%20%5B%5Cfrac%7B1%7D%7BR_1%7D%20-%20%5Cfrac%7B1%7D%7BR_2%7D%20%20%5D)
Where
is the focal length
is the index of refraction
are the radius of curvature of sphere 1 and 2 of the lens
From the question When the lens in air we have
![\frac{1}{f_{air}} = (n-1) [\frac{1}{R_1} - \frac{1}{R_2} ]](https://tex.z-dn.net/?f=%5Cfrac%7B1%7D%7Bf_%7Bair%7D%7D%20%3D%20%28n-1%29%20%5B%5Cfrac%7B1%7D%7BR_1%7D%20-%20%5Cfrac%7B1%7D%7BR_2%7D%20%20%5D)
When immersed in liquid the formula becomes
![\frac{1}{f_{water}} = [\frac{n_2}{n_1} - 1 ] [\frac{1}{R_1} - \frac{1}{R_2} ]](https://tex.z-dn.net/?f=%5Cfrac%7B1%7D%7Bf_%7Bwater%7D%7D%20%3D%20%5B%5Cfrac%7Bn_2%7D%7Bn_1%7D%20-%201%20%5D%20%5B%5Cfrac%7B1%7D%7BR_1%7D%20-%20%5Cfrac%7B1%7D%7BR_2%7D%20%20%5D)
The ratio of the focal length of the the two medium is mathematically evaluated as
![\frac{f_water}{f_{air}} = \frac{n_2 -1}{[\frac{n_2}{n_1} - 1] }](https://tex.z-dn.net/?f=%5Cfrac%7Bf_water%7D%7Bf_%7Bair%7D%7D%20%3D%20%5Cfrac%7Bn_2%20-1%7D%7B%5B%5Cfrac%7Bn_2%7D%7Bn_1%7D%20-%201%5D%20%7D)
From the question
= 79.0 cm

and the refractive index of water(material surrounding the lens) has a constant value of 


b
The focal length of a mirror is dependent on the concept of reflection which is not affected by medium around it.
Answer:
V2 = 15.53 [m/s]]
Explanation:
In order to solve this problem we must use the principle of energy conservation, where potential energy is transformed into kinetic energy. At the bottom is taken as a reference level of potential energy, where the value of this energy is equal to zero.
Above the inclined plane we have two energies, kinetics and potential. While when the sled is at the reference level all this energy will have been transformed into kinetic energy.
![E_{1}=E_{2}\\ m*g*h+(\frac{1}{2} )*m*v_{1} ^{2}=\frac{1}{2}*m*v_{2} ^{2} \\(9.81*8.21)+(0.5*8.96^{2} )=(0.5*v_{2}^{2} )\\(0.5*v_{2}^{2} )=120.68\\v_{2} ^{2}=241.36\\v_{2} =\sqrt{241.36}\\ v_{2} =15.53[m/s]](https://tex.z-dn.net/?f=E_%7B1%7D%3DE_%7B2%7D%5C%5C%20%20m%2Ag%2Ah%2B%28%5Cfrac%7B1%7D%7B2%7D%20%29%2Am%2Av_%7B1%7D%20%5E%7B2%7D%3D%5Cfrac%7B1%7D%7B2%7D%2Am%2Av_%7B2%7D%20%5E%7B2%7D%20%5C%5C%289.81%2A8.21%29%2B%280.5%2A8.96%5E%7B2%7D%20%29%3D%280.5%2Av_%7B2%7D%5E%7B2%7D%20%29%5C%5C%280.5%2Av_%7B2%7D%5E%7B2%7D%20%29%3D120.68%5C%5Cv_%7B2%7D%20%5E%7B2%7D%3D241.36%5C%5Cv_%7B2%7D%20%3D%5Csqrt%7B241.36%7D%5C%5C%20%20v_%7B2%7D%20%3D15.53%5Bm%2Fs%5D)
Solids have the highest density. Then comes liquid and the less dense one is gas.