Answer:
r₂ = 0.2 m
Explanation:
given,
distance = 20 m
sound of average whisper = 30 dB
distance moved closer = ?
new frequency = 80 dB
using formula

I₀ = 10⁻¹² W/m²
now,



to hear the whisper sound = 80 dB



we know intensity of sound is inversely proportional to square of distances



r₂ = 0.2 m
To solve this problem we will begin by finding the necessary and effective distances that act as components of the centripetal and gravity Forces. Later using the same relationships we will find the speed of the body. The second part of the problem will use the equations previously found to find the tension.
PART A) We will begin by finding the two net distances.

And the distance 'd' is



Through the free-body diagram the tension components are given by


Here we can watch that,

Dividing both expression we have that,

Replacing the values,


PART B) Using the vertical component we can find the tension,




Time period = 1 / frequency
Time period = 1 / 250 th of a second
Answer:

Explanation:
Given that
Speed ,v= 2 x 10⁵ m/s ( - y direction)
B= 0.6 T (- z direction)
The resultant force on the proton given as

F= m a
For uniform motion acceleration should be zero.
F = 0






Electric filed should be apply in the negative x direction.