Physics
A standing wave occurs when

Two waves overlap
The speed of the wave is zero or near zero
The amplitude of a wave exceeds its wavelength
A wave reflects upon itself

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Physics
A cyclist leans inwards when he is negotiating a curve so that

Necessary centripetal force may be available from the horizontal component of the normal reaction due to the track to maintain the curved motion.
No frictional force may be produced between the wheels and the axle
His weight may be reduced
He may increase his speed

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