Answer:
The speed of q₂ is 
Explanation:
Given that,
Distance = 0.4 m apart
Suppose, A small metal sphere, carrying a net charge q₁ = −2μC, is held in a stationary position by insulating supports. A second small metal sphere, with a net charge of q₂ = −8μC and mass 1.50g, is projected toward q₁. When the two spheres are 0.800m apart, q₂ is moving toward q₁ with speed 20m/s.
We need to calculate the speed of q₂
Using conservation of energy



Put the value into the formula






Hence, The speed of q₂ is 
Build walls around the coast
Answer:
the ans is D... good luck
To develop the problem it is necessary to apply the kinematic equations for the description of the position, speed and acceleration.
In turn, we will resort to the application of Newton's second law.
PART A) For the first part we look for the time, in a constant acceleration, knowing the speeds and the displacement therefore we know that,

Where,
X = Desplazamiento
V = Velocity
t = Time
In this case there is no initial displacement or initial velocity, therefore

Clearing for time,



PART B) This is a question about the impulse of bodies, where we turn to Newton's second law, because:
F = ma
Where,
m=mass
a = acceleration
Acceleration can also be written as,

Then





Negative symbol is because the force is opposite of the direction of moton.
PART C) Acceleration through kinematics equation is defined as




The gravity is equal to 0.8, then the acceleration is


Answer:
4.6 kHz
Explanation:
The formula for the Doppler effect allows us to find the frequency of the reflected wave:

where
f is the original frequency of the sound
v is the speed of sound
vs is the speed of the wave source
In this problem, we have
f = 41.2 kHz
v = 330 m/s
vs = 33.0 m/s
Therefore, if we substitute in the equation we find the frequency of the reflected wave:

And the frequency of the beats is equal to the difference between the frequency of the reflected wave and the original frequency:
