Answer:
vavg = 53.7 km/h
Explanation:
In order to find the magnitude of the bus'average velocity, we need just to apply the definition of average velocity, as follows:
where xf - xo = total displacement = 1250 Km
If we choose t₀ = 0, ⇒ t = 23h 16'= 23h + 0.27 h = 23.27 h
⇒ 
A machine can never be 100% efficient because some work is always lost
due to the lack of materials or equipment that would convert work by 100%. It follows
the second law of entropy. The ideal engine is known as Carnot’s engine having
a 100% efficiency. So far, no engine has ever gotten to 100%.
Answer: option (D)
Explanation:
The potential energy of each of the students is given below as
P.E(student A) = mgh, where m = mass of student A, g is acceleration due to gravity and h = height of the high dive structure.
The mass of student B is twice as much as that of A, hence his mass is 2m and his potential energy is given below as
P.E ( student B) =2mgh = 2(mgh)
Recall that the relationship between potential energy and work done is that
Work done = - (change in potential)
For student A, work done = - mgh
For student B, work done = - 2mgh
From the equations above it can be seen that student B will do twice the work in getting to the high dive structure than student A hence validating option D.
The wavelength of a sound wave is related to its frequency by the relationship:
where
f is the frequency
v is the speed of the wave
is the wavelength
The wave in our problem has wavelength of
and speed of
(this is the speed of sound in air), therefore its frequency is
And the period of the wave is equal to the reciprocal of its frequency:
Боже, как это сложно! Ну ладно.
Между прочим это ты сам должен делать, а то не куда не поступишь!
