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
Answer:
3 1/20
Step-by-step explanation:
First, we will convert the mixed numbers into improper fractions...
9 3/10 (9*10=90+3=93) so the improper fraction is 93/10
5 3/4 (5*4=20+3=23) therefore the improper fraction is 23/4
We then want to make the denominator the same...
93/10 (*4) = 372/40
23/4 (*10) = 230/40
We then put it into the question...
372/40 - 230/40 = 142/40
Lastly, we now need to turn this into a mixed number...
142/40=3.55 so the answer is 3 2/40
3 2/40 in it's simplest form is 3 1/20
Hope this helps!
20 is the slope and 30 is the y-intercept
121 rounded to the nearest 100 is 100 because 121 is closer to 100 than 200.
252 rounded to the nearest hundred is 300 because 252 is closer to 300 than 100.
The answer is A, the first one :)