Pls help with this qn. Thx!

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# Question

# Answer

Adwin

i) If “a” is directly proportional to “b”, this means that a = k x b, where k is a constant. If “a” is inversely proportional to “b”, this means that a = k x 1/b, where k is a constant.

Since we know that F is inversely proportional to the square of d, this means that the equation is:

F = k x 1/d^{2}

**F = k/d ^{2}**

b) When d is halved, d becomes d/2,

so, F = k / (d/2)^{2}

F = k/ (d^{2}/4)

F = 4k/d^{2}

From this, we can tell that **when d is halved, the force of repulsion is quadrupled (x4)**.

Therefore, the force when d is halved is:

20 Newtons x 4 = **80 Newtons**

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