Question

Elston attaches a spring scale to a box and pulls it across the floor. He then places a book in the box and pulls it the same distance with the same acceleration. How does the force shown on the spring scale change after the book is placed in the box?

A. It increases.
B. It decreases.
C. It remains the same.
D. It fluctuates.

Answer 1

The force shown on the spring scale will increase when a book is added to the box, because the total mass increases while the same acceleration is maintained.

Step-by-step explanation:

When Elston attaches a spring scale to a box and pulls it across the floor, the force shown on the scale is related to the mass of the box and the acceleration it undergoes. According to Newton's second law of motion, F = ma, where F is the force, m is the mass, and a is the acceleration. When Elston places an additional book in the box and pulls with the same acceleration across the same distance, the total mass of the box system increases. Therefore, to achieve the same acceleration, a greater force must be applied. As a result, the force shown on the spring scale will increase.

The correct answer to the question is (A) It increases.