Let current be I, charge be Q and time be t.
Here we are provided with,
I = 0.72A
t = 4s / 60s / 180s / 7s / 0.5s
We know,
I = Q/t
Case I
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When, t = 4s
0.72 = Q/4
Q = 0.72 * 4 = 2.88C
Case II
----------
When, t = 60s
0.72 = Q/60
Q = 0.72 * 60 = 43.2C
Case III
-----------
When, t = 180s
0.72 = Q/180
Q = 0.72 * 180 = 129.6C
Case IV
-----------
When, t = 7s
0.72 = Q/7
Q = 0.72 * 7 = 5.04C
Case V
----------
When, t = 0.5s
0.72 = Q/0.5
Q = 0.72 * 0.5 = 0.36C
Answer: 
Explanation:
The frequency 
of a wave is given by the following equation:
Where:
is the period
Hence:
The working equation for this problem is a derived equation from the rectilinear motion at constant acceleration. The equation is written below:
2ax = v² - v₀²
where
a is the acceleration
x is the distance
v is the final velocity
v₀ is the initial velocity
Of course, the plane starts from rest, so v₀ = 0. The final velocity is the liftoff speed which is v = 120 km/h. Substituting the values:
2a(270 m) = (120 km/h)² - 0²
Solving for a,
a = 26.67 km/h²
Let, 1st force = a
2nd force = b
A.T.Q,
a+b = 10
a-b = 6
Calculate for a & b, you'll get a=8 & b= 2
After increasing by 3, it'll be a = 8+3 = 11 & b=2+3 = 5
Resultant force at 90 degree angle = 11+5 = 16 Newtons
Balanced forces is the answer.
