A 20-Kg Block Is Attached to One End of a Spring

question 88

Multiple Choice

A 2.0-kg block is attached to one end of a spring with a spring constant of 100 N/m and a 4.0-kg block is attached to the other end.The blocks are placed on a horizontal frictionless surface and set into motion.At one instant the 2.0-kg block is observed to be traveling to the right with a speed of 0.50 m/s and the 4.0-kg block is observed to be traveling to the left with a speed of 0.30 m/s.Since the only forces on the blocks are the force of gravity, the normal force of the surface, and the force of the spring, we conclude that:

• A)the spring is compressed at the time of the observation
• B)the spring is not compressed at the time of observation
• C)the motion was started with the masses at rest
• D)the motion was started with at least one of masses moving
• E)the motion was started by compressing the spring

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Definitions:

Endowed

Provided with a quality, ability, or asset; in economics, it often refers to the resources or goods that an individual or institution possesses.

Pareto Optimal Allocation

An economic allocation where it is impossible to make any one individual better off without making at least one individual worse off.

Utility Function

A mathematical representation that assigns a level of utility or satisfaction to various combinations of goods and services consumed by an individual or society.

Consumers

Individuals or entities that use or consume goods and services produced within an economy.