A 3.00 lb. physics book rests on an ordinary scale that is placed on a horizontal table.
The reaction force to the downward 3.00 lb force on the book is
A. an upward 3.00 lb force on the scale due to the table.
B.an upward 3.00 lb force on the book due to the scale.
C.an upward 3.00 lb force on the table due to the floor.
D.an upward 3.00 lb force on the earth due to the book.
To determine the reaction force to the downward force on the book, we need to understand Newton's third law of motion which states that every action has an equal and opposite reaction.
In this case, the downward force on the book is exerted by gravity. According to Newton's third law, the reaction force will be equal in magnitude but opposite in direction to the downward force.
Therefore, the reaction force to the downward 3.00 lb force on the book will be an upward force. Let's analyze the answer choices:
A. an upward 3.00 lb force on the scale due to the table.
B. an upward 3.00 lb force on the book due to the scale.
C. an upward 3.00 lb force on the table due to the floor.
D. an upward 3.00 lb force on the earth due to the book.
Out of these options, the most appropriate one would be A: an upward 3.00 lb force on the scale due to the table. The scale measures the force exerted by the book, and since the scale is placed on a horizontal table, the reaction force to the downward force on the book is an upward force on the scale due to the table.