Answer: 
Explanation:
We know the total diameter of the cell (assumed spherical) is:

Then its total radius 
On the other hand, we know the thickness of the cell wall is
and its density is the same as water (
).
Since density is the relation between the mass
and the volume
:

The mass is:
(1)
Now if we are talking about this cell as a thin spherical shell, its volume will be:
(2)
Where 
Then:
(3)
(4)
Substituting (4) in (1):
(5)
(6)
Knowing
and
:
Answer:
Explanation:
The spring is stretched by .5 m and then released that means its amplitude of oscillation A is 0.5 m .
A = 0.5 m
After the release at one extreme point , the mass comes to rest again at another extreme point after half the time period ie
T / 2 = .3 s
T = 0.6 s
Angular velocity
ω = 
ω = 
ω = 10.45
Maximum velocity = ω A
ω and A are angular velocity and amplitude of oscillation.
Maximum velocity = 10.45 x .5
= 5.23 m /s
I believe you got it correct already
So looking at the problem, you are going to want to start by finding a common denominator (1) in this case: yb, and combining like terms (2). You are then going to want to multiply both sides by (yb) as the reciprocal to the fractions (3).
1) 3x 6g
---- = ---
y b
2) 3xb 6gy
------ = -----
yb yb
3) 3xb 6gy
(yb) ------ = -----
yb yb
which becomes: 3xb = 6gy
So after this, things become much more simple, as all you have to do is isolate the (x), which can be done by dividing the entire equation by (3b).
3xb 6gy
----- = -----
3b 3b
where you will then find your answer of:
2gy
x = ----- (simplified by the GCM of 3)
b