Answer:
correct option is C) 2.8
Step-by-step explanation:
given data
string vibrates form = 8 loops
in water loop formed = 10 loops
solution
we consider mass of stone = m
string length = l
frequency of tuning = f
volume = v
density of stone =
case (1)
when 8 loop form with 2 adjacent node is
so here
..............1

and we know velocity is express as
velocity = frequency × wavelength .....................2
= f ×
here tension = mg
so
= f ×
..........................3
and
case (2)
when 8 loop form with 2 adjacent node is
..............4

when block is immersed
equilibrium eq will be
Tenion + force of buoyancy = mg
T + v ×
× g = mg
and
T = v ×
- v ×
× g
from equation 2
f ×
= f ×
.......................5
now we divide eq 5 by the eq 3

solve irt we get

so
relative density 
relative density = 2.78 ≈ 2.8
so correct option is C) 2.8
For each of the following relationships, graph the proportional relationship between the two quantities, write the equation representing the relationship, and describe how the unit rate, or slope is represented on the graph.
I think it'd be 9 seconds, not 100% sure though.
Hello there.
Answer: Split the shape into two
Calculate both shapes separately
10 x 10 x 10 = 1000
20 x 20 x 20 = 8000.
Add together both values:
8000 + 1000 = 9000in³
Hope Thus Helps You!
Good Luck Studying ^-^