Answer:
I think it's 2 the photo is hard to tell what they are exactly talking about.
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:
Atomic mass is defined as the number of protons and neutrons in an atom, where each proton and neutron has a mass of approximately 1 amu (1.0073 and 1.0087, respectively). The electrons within an atom are so miniscule compared to protons and neutrons that their mass is negligible.
I hope this is the answer you were looking for :D
Answer:
3331.5 kg
Explanation:
Given:
Spring constant of the spring (k) = 24200 N/m
Frequency of oscillation (f) = 0.429 Hz
Let the mass be 'm' kg.
Now, we know that, a spring-mass system undergoes Simple Harmonic Motion (SHM). The frequency of oscillation of SHM is given as:

Rewrite the above equation in terms of 'm'. This gives,

Now, plug in the given values and solve for 'm'. This gives,

Therefore, the mass of the truck is 3331.5 kg.