A scale in an elevator accelerates upward; the scale reading changes with acceleration. Which statement is true?

A scale in an elevator accelerates upward; the scale reading changes with acceleration. Which statement is true?

• A. The scale reading decreases as acceleration increases.
• B. The scale reading increases linearly with acceleration.
• C. The scale reading remains unchanged.
• D. The scale reading becomes zero when acceleration equals g.

Answer: (B)

When you’re in an elevator, the scale reading is your apparent weight—the normal force the scale must exert on you. If the elevator accelerates upward with acceleration a, Newton’s second law applied to you (taking upward as positive) gives N − mg = m a. Solving for the scale reading gives N = m(g + a). This means the reading increases linearly as the upward acceleration grows—you feel heavier as the elevator speeds up upward, and the change is proportional to a with slope m. It’s not unchanged, and it’s not zero when a equals g (that would require a downward acceleration of g).

When you’re in an elevator, the scale reading is your apparent weight—the normal force the scale must exert on you. If the elevator accelerates upward with acceleration a, Newton’s second law applied to you (taking upward as positive) gives N − mg = m a. Solving for the scale reading gives N = m(g + a). This means the reading increases linearly as the upward acceleration grows—you feel heavier as the elevator speeds up upward, and the change is proportional to a with slope m. It’s not unchanged, and it’s not zero when a equals g (that would require a downward acceleration of g).