Answer:
0.16Hz
Explanation:
wavelength (λ) = 125 meters
speed (V) = 20 m/s
frequency (F) = ?
Recall that frequency is the number of cycles the wave complete in one
second. And its value depends on the wavelength and speed of the wave.
So, apply the formula V = F λ
Make F the subject formula
F = V / λ
F = 20 m/s / 125 meters
F = 0.16 Hz
Lower resistivity means higher conductivity: among these materials, the best conductor is silver, therefore it must be the material with lowest resistivity among those. We can also have a look at the value of resistivity of the different materials listed in the problem, to check our answer. The resistivities of the materials are the following:
Wood:

Salt water:

Silver:

Lead:

<span>We see that the material with lowest resistivity among those is silver, therefore the correct answer is silver.</span>
Answer:

Explanation:
First of all, we need to find the pressure exerted on the sphere, which is given by:

where
is the atmospheric pressure
is the water density
is the gravitational acceleration
is the depth
Substituting,

The radius of the sphere is r = d/2= 1.1 m/2= 0.55 m
So the total area of the sphere is

And so, the inward force exerted on it is

This being a perfect collision means no energy is lost during the collision. Because this question asks for speed and not velocity, the speed will be the same because the final energy is the same. The speed after the collision would therefore be 1.27 m/s.
because water is loosely packed but when it is cold it becomes closely packed in order to form ice and thus the force attraction between them also increase.