Answer:
Explanation:
Given that,
A point charge is placed between two charges
Q1 = 4 μC
Q2 = -1 μC
Distance between the two charges is 1m
We want to find the point when the electric field will be zero.
Electric field can be calculated using
E = kQ/r²
Let the point charge be at a distance x from the first charge Q1, then, it will be at 1 -x from the second charge.
Then, the magnitude of the electric at point x is zero.
E = kQ1 / r² + kQ2 / r²
0 = kQ1 / x² - kQ2 / (1-x)²
kQ1 / x² = kQ2 / (1-x)²
Divide through by k
Q1 / x² = Q2 / (1-x)²
4μ / x² = 1μ / (1 - x)²
Divide through by μ
4 / x² = 1 / (1-x)²
Cross multiply
4(1-x)² = x²
4(1-2x+x²) = x²
4 - 8x + 4x² = x²
4x² - 8x + 4 - x² = 0
3x² - 8x + 4 = 0
Check attachment for solution of quadratic equation
We found that,
x = 2m or x = ⅔m
So, the electric field will be zero if placed ⅔m from point charge A, OR ⅓m from point charge B.
Bcoz when you place a magnet close enough the magnet attracts or repals without any other fore we dont touch the magnet so it is non contact
Answer:
1.2 x 
N
Explanation:
The centripetal force of a body moving in a circle is given by:
Centripetal force = 
where M = mass of the object, v = velocity with which the object is moving, and r = radius of the circle.
In this case, M = 25,000 kg, v = 2.0 m/s, and r = 8.2 m. Hence;
Centripetal force generated by the whale = 25,000 x 2^2/8.2
= 12,195.12 N = 1.2 x N to two significant digits.
1) sound velocity reported by you : 292.39 m /s
2) time to travel 1620m at that velocity: t = d / v = 1620 m / 292.39 m/s = 5.54 s, since the moment the sound wave started.
3) You might wanted to tell the time since you watched the lightning.
Then you can calculate the time since the lighting was generated,1620 m away from you, until you saw it, using the speed of light:
speed of light = 3*10^8 m/s => t = 1620 m / (3*10^8m/s) =0.0000054 s
Then, this time is completely neglectible, and yet the answer is 5.54 s, as calculated in the step 2.
