A bead starts from rest at point $P$ and moves along a wire, as shown. The track bends round to form a vertical circle with diameter $40\,\text{cm}$. At point $Q$, the bead’s speed is $1.4\,\text{m s}^{-1}$. Air resistance and friction on the wire are negligible. What is the height $h$ from which the bead is released?
- A$0.30\,\text{m}$
- B$0.40\,\text{m}$
- C$0.50\,\text{m}$
- D$0.60\,\text{m}$