The weight required to stretch the spring 12.5 cm is 7.5 N (Option A)
The new weight required to stretch the spring can be obtained as follow:
W₁ / L₁ = W₂ / L₂
3 / 5 = W₂ / 12.5
Cross multiply
W₂ × 5 = 3 × 12.5
Divide both sides by 5
W₂ = (3 × 12.5) / 5
W₂ = 7.5 N
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