Answer: Option (b) is the correct answer.
Explanation:
The given data is as follows.
F = 
N
g = 9.8 m/s
radius = 
= 
= 15 cm = 0.15 m (as 1 m = 100 cm)
Formula to calculate depth is as follows.
F = 
or, h = 
h = 
= 751 m
Thus, we can conclude that the maximum depth in a lake to which the submarine can go without damaging the window is closest 750 m.
Answer:
Explanation:
The unknown charge can not remain in between the charge given because force on the middle charge will act in the same direction due to both the remaining charges.
So the unknown charge is somewhere on negative side of x axis . Its charge will be negative . Let it be - Q and let it be at distance - x on x axis.
force on it due to rest of the charges will be equal and opposite so
k3q Q / x² =k 8q Q / (L+x)²
8x² = 3 (L+x)²
2√2 x = √3 (L+x)
2√2 x - √3 x = √3 L
x(2√2 - √3 ) = √3 L
x = √3 L / (2√2 - √3 )
Let us consider the balancing force on 3q
force on it due to -Q and -8q will be equal
kQ . 3q / x² = k3q 8q / L²
Q = 8q (x² / L²)
so charge required = - 8q (x² / L²)
and its distance from x on negative x side = √3 L / (2√2 - √3 )
882 divided by 9.81 (this is acceleration due to gravity) it equals 89.91
Ruff's image is 50m behind the mirror surface and the image is also 3m tall.
This is because it is a plane mirror.
