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:

Trophic Level

Position of an organism in a food chain.

Chaparral Biome

A biome characterized by dense, spiny shrubs and a Mediterranean climate, with hot, dry summers and mild, wet winters, typically found in California and the Mediterranean region.

Primary Production

The rate at which an ecosystem’s producers capture and store energy.

Temperate Deciduous Forest

Northern Hemisphere biome in which the predominant plants are broadleaf trees that lose their leaves in fall and become dormant during cold winters.