# A classical mechanics problem by Yahia El Haw

A $$1.2\text{ kg}$$ mass is projected down a rough semi-circular vertical track of radius $$2.0 \text{ m}$$, as shown in the diagram below. The speed of the mass at point $$A$$ is $$3.2\text{ m/s}$$, and that at point $$B$$ is $$6.0 \text{ m/s}$$.

How much work is done on the mass between $$A$$ and $$B$$ by the force of friction?

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