A Softball Player Determines Her Pitching Speed by Throwing a Ball

question 78

Multiple Choice

A softball player determines her pitching speed by throwing a ball horizontally from an elevation of 20 m above the ground.The ball lands 50 m downrange.What is her pitching speed?

• A)5 m/s
• B)10 m/s
• C)20 m/s
• D)25 m/s
• E)none of the above

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Definitions:

Alpha Emitter

A type of radioactive decay in which an unstable atom emits an alpha particle consisting of two protons and two neutrons, thereby reducing its atomic number by 2 and mass number by 4.

Nitrogen

A colorless, odorless, tasteless gas that constitutes approximately 78% of the Earth's atmosphere and is a vital part of living organisms' compounds.

Helium

Helium is a colorless, odorless, tasteless, non-toxic, inert, monatomic gas that heads the noble gas series in the periodic table, with the symbol He and atomic number 2.

Oxygen

A chemical element with symbol O and atomic number 8, essential for respiration in living organisms and a component of air.