A cricketer lowers his hand while catching balls. Why?
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Why is alchemy not considered to be a science ?

Arock,thrown straight up, takes 4.2 seconds to reach its max height (g=9.8m/s) what was the initial velocity? what was its maximum height?

The earth's magnetic field, with a magnetic dipole moment of 8.0×1022am2, is generated by currents within the molten iron of the earth's outer core. suppose we model the core current as a 3000-km-diameter current loop made from a 1000-km-diameter “wire.” the loop diameter is measured from the centers of this very fat wire.to decide whether this is a large or a small current density, compare it to the current density of a 7.0 a current in a 2.0-mm-diameter wire.