To solve the exercise it is necessary to take into account the definition of speed as a function of distance and time, and the speed of air in the sound, as well

Where,
V= Velocity
d= distance
t = time
Re-arrange the equation to find the distance we have,
d=vt
Replacing with our values


It is understood that the sound comes and goes across the entire lake therefore, the length of the lake is half the distance found, that is



Therefore the length of the lake is 634,55m
Answer:
D. transparent.
Explanation:
A material that transmits nearly all the light in a ray because it offers little resistance to the light is <u>transparent.</u>
A transparent material allows light to pass through them with little or no resistance enabling them see-through. A material that transmits nearly all the light rays that pass through it because it offers little resistance to the light is TRANSPARENT. Examples of transparent materials are water, glass (flint and crown), air, and diamond.
Answer:
R = 7 [amp]
Explanation:
To solve this problem we must use ohm's law which tells us that the voltage is equal to the product of the current by the resistance. In this way, we have the following equation.
V = I*R
where:
V = voltage = 49 [V] (units of volts)
I = current = 7 [amp] (amperes)
R = resistance [ohms]
Now clearing R.
R =V/I
R = 49/7
R = 7 [amp]
Answer:
(A) Acceleration will be 
(b) Time taken will be 
(c) Force will be
Explanation:
We have given that electron starts from rest so initial velocity u = 0 m/sec
Final velocity 
Mass of electron 
Distance traveled by electron 
From third equation of motion we know that 
(a) So 

(b) From first equation of motion we know that v = u+at
So 

(c) From newton's law we know that force
