Answer:
Explanation:
Given that,
Frequency of a radio antenna is 1 MHz
Power, P = 21 kW
We need to find the the waves intensity 25 km from the antenna
. The object emits intenisty evenly in all direction. It can be given by :
So, the wave intensity 25 km from the antenna is 
.
Answer:
c it is not accelerating on it's on but gravity pulls it there for velocity increases.
5kg
50cm
500in
Hope this helped good luck to you
Answer:
a) 0.018 kg
b) 262 kPa
Explanation:
The volume of the concentric cylinders would be:
V = π/4 * h * (D^2 - d^2)
V = π/4 * 13 * (52^2 - 33^2) = 16500 cm^3 = 0.0165 m^3
The state equation of gases:
p * V = m * R * T
Rearranging:
m = (p * V) / (R * T)
R is 287 J/(kg * K) for air
25 C = 298 K
m0 = 202000 * 0.0165 / (287 * 298) = 0.039 kg
After pumping more air the volume remains about the same, but temperature and pressure change.
30 C = 303 K
m1 = 303000 * 0.0165 / (287 * 303) = 0.057 kg
The mass that was added is
m1 - m0 = 0.057 - 0.039 = 0.018 kg
If that air is cooled to 0 C
0 C is 273 K
p = m * R * T / V
p = 0.057 * 278 * 273 / 0.0165 = 262000 Pa = 262 kPa
Answer:
(a) v1 = 21.6 m/s
(b) t = 51.25 s
Explanation:
Use kinematics equation
v1 = v0 + at
Given
v0 = 0 = initial velocity
a = 0.8 m/s^2 = acceleration
(a) t = 27 seconds
v1 = v0 + at = 0 + 0.8*27 = 21.6 m/s
(b) v1 = 41 m/s
v1 = v0 + at
solve for t
t = (v1-v0)/a = (41-0)/0.8 = 51.25 s
