A Boy Pulls a Wooden Box Along a Rough Horizontal

question 25

Multiple Choice

A boy pulls a wooden box along a rough horizontal floor at constant speed by means of a force as shown.In the diagram f is the magnitude of the force of friction, N is the magnitude of the normal force, and F_g is the magnitude of the force of gravity.Which of the following must be true?

• A)P = f and N = F_g
• B)P = f and N > F_g
• C)P > f and N < F_g
• D)P > f and N = F_g
• E)none of these

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Definitions:

Analogy

A comparison between two things, typically for the purpose of explanation or clarification.

Neurotransmitter

Chemical messengers that transmit signals across a chemical synapse from one neuron (nerve cell) to another 'target' neuron, muscle cell, or gland cell.

Receptor Site

A specific location on a cell membrane or within a cell where molecules such as hormones, neurotransmitters, or drugs can bind to elicit a physiological response.

Excitatory

Referring to signals or substances that increase the likelihood of a neuron firing an action potential.