A Lamp of Mass M Hangs from a Spring Scale

question 12

Multiple Choice

A lamp of mass m hangs from a spring scale that is attached to the ceiling of an elevator.When the elevator is stopped at the fortieth floor,the scale reads mg.What does it read while the elevator descends toward the ground floor at a constant speed?

• A)more than mg
• B)less than mg
• C)mg
• D)zero
• E)This cannot be answered without knowing how fast the elevator is descending.