A 25-Kg Block on a Horizontal Surface Is Attached to a Light

question 31

Multiple Choice

A 25-kg block on a horizontal surface is attached to a light spring (force constant = 8.0 kN/m) . The block is pulled 10 cm to the right from its equilibrium position and released from rest. When the block has moved 2.0 cm toward its equilibrium position, its kinetic energy is 12 J. What is the change in mechanical energy caused by the frictional force on the block as it moves the 2.0 cm?

• A) −4.0 J
• B) −3.5 J
• C) −2.4 J
• D) −2.9 J
• E) −15 J

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Definitions:

Neonates

Newborn infants, especially those less than four weeks old.

Mongolian Spots

Benign, flat birthmarks with a blueish or bluish-grey coloration, commonly found on infants and usually fading over time.

Deep Blue Pigmentation

A description often used for certain types of skin discoloration that can signify underlying medical conditions.

Newborns

Infants who are in the first few weeks of life, typically considered to be up to 28 days old.