Question

The answer is 4m
I need solution for this question with clear explaination​

Answer 1

Answer:

By energy conservation

$mgh = \frac{1}{2} m {v}^{2} \\ v = \sqrt{40} \\ from \: b \: to \: c \\ mgh2 \: = \frac{1}{2}m {v}^{2} \\ \: h2 \ = 2m \\ \sin(30) = \frac{2}{bc} \\ bc \: = 4$

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