The frequency of the radio wave is:

The wavelength of an electromagnetic wave is related to its frequency by the relationship

where c is the speed of light and f the frequency. Plugging numbers into the equation, we find

and this is the wavelength of the radio waves in the problem.
Answer:
Explanation:
Given mg = 4N .
m = 4 / g
At the bottom of the swing let centripetal acceleration be a
T - mg = ma
9 - 4 = ma
5 = 4 a / g
a = 5g / 4
For Newton's second law, the resultant of the forces acting on the book is equal to the product between the mass of the book and its acceleration:

(1)
There are only two forces acting on the book:
- its weight, directed downward: mg
- the force exerted by the hand on the book, of 20 N, directed upward
so, equation (1) becomes

from which we can calculate the book's acceleration, a:
Answer:
1340.2MW
Explanation:
Hi!
To solve this problem follow the steps below!
1 finds the maximum maximum power, using the hydraulic power equation which is the product of the flow rate by height by the specific weight of fluid
W=αhQ
α=specific weight for water =9.81KN/m^3
h=height=220m
Q=flow=690m^3/s
W=(690)(220)(9.81)=1489158Kw=1489.16MW
2. Taking into account that the generator has a 90% efficiency, Find the real power by multiplying the ideal power by the efficiency of the electric generator
Wr=(0.9)(1489.16MW)=1340.2MW
the maximum possible electric power output is 1340.2MW
Answer:
please read the answer below
Explanation:
The angular momentum is given by

By taking into account the angles between the vectors r and v in each case we obtain:
a)
v=(2,0)
r=(0,1)
angle = 90°

b)
r=(0,-1)
angle = 90°

c)
r=(1,0)
angle = 0°
r and v are parallel
L = 0kgm/s
d)
r=(-1,0)
angle = 180°
r and v are parallel
L = 0kgm/s
e)
r=(1,1)
angle = 45°

f)
r=(-1,1)
angle = 45°
the same as e):
L = 5kgm/s
g)
r=(-1,-1)
angle = 135°

h)
r=(1,-1)
angle = 135°
the same as g):
L = 5kgm/s
hope this helps!!