A 60-Kg Block Slides Along a Horizontal Surface

question 68

Multiple Choice

A 6.0-kg block slides along a horizontal surface. If µ_k = 0.20 for the block and surface, at what rate is the friction force changing the mechanical energy of the block at an instant when its speed is 4.0 m/s?

• A) −59 W
• B) −47 W
• C) −71 W
• D) −82 W
• E) +71 W

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Definitions:

Less Developed Countries

Nations with lower living standards, undeveloped industrial bases, and low Human Development Index (HDI) relative to other countries.

Annual Rate

A rate of interest, growth, or performance measured over a twelve-month period.

Food Supply

The total amount of food available to feed a population, encompassing production, distribution, and stocks of foodstuffs.

Thomas Malthus

An English cleric and scholar influential in the fields of political economy and demography, best known for his theory that population growth would outpace agricultural production leading to famine.