<span>The purpose of pumping is to increase overall velocity. The person drops down into a crouch while traversing the more-or-less flat bottom of the U-shaped pipe or bowl. Then, as he enters the sloped part of the ramp or bowl, called the transition, he straightens his legs and rises up. By raising his center of mass just at the beginning of the arc, the person gains energy and thereby increases his speed.</span>
The elasticity of a polymer is primarily due to the structure of the molecule and the cross-linking between strands. Hydrogen bonding is a contributor to the shape of the molecule, but not a major player in terms of elasticity. We would have to answer "false".
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We simply asked to name three uses for mercury.
The most common and well-known use of mercury is the production of thermometers. It's property to stay liquid at room temperature makes it ideal for a temperature indicator. However, the use of mercury is thermometers has been phased out due to health hazards.
It is also used to form an amalgam which is the result of its combination with silver or gold. Mercury has been used to mine gold and silver. This application has also been phased out.
Today's use of mercury includes mercury-vapor lamps which are the bright lamps used in high-ways.
This would be false. hope this helps. good luck :)