Answer:
oo.p i wish I could answer that
Explanation:
It has been hypothesized, and some studies have supported the conjecture,
that certain species of insects and birds are able to sense the direction of external
magnetic fields.
I don't think there is any such notion where human beings are concerned.
Ans: Time <span>taken by a pulse to travel from one support to the other
= 0.348s</span>
Explanation:First you need to find out the speed of the wave.
Since
Speed = v =

Where
T = Tension in the cord = 150N
μ = Mass per unit length = mass/Length = 0.65/28 = 0.0232 kg/m
So
v =

= 80.41 m/s
Now the time-taken by the wave = t = Length/speed = 28/80.41=
0.348s
V = [4/3]π r^3 => [dV / dr ] = 4π r^2
[dV/dt] = [dV/dr] * [dr/dt]
[dV/dt] = [4π r^2] * [ dr/ dt]
r = 60 mm, [dr / dt] = 4 mm/s
[dV / dt ] = [4π(60mm)^2] * 4mm/s = 180,955.7 mm/s