Question Detail
Question
A 2 kg block hangs from a spring balance which is attached to the roof of an elevator. What does the balance read when the elevator is moving up with a constant velocity of 30 m/s? (acceleration due to gravity, g = 10 m/s²)
Correct Answer
Option D is the correct answer.
Detailed Explanation
When the elevator moves with constant velocity, there is no acceleration. The spring balance measures the tension which equals the weight. Weight = mg = 2 kg × 10 m/s² = 20 N. So the balance reads 20 N.
Hint
In the absence of acceleration, the force measured by a scale is the true weight.