a 6kg mass hangs from a spring scale. What would the scale reading be if the spring scale moves up at a constant velocity of 2m/s? What about moving down at a constant velocity of 2m/s?

Question

a 6kg mass hangs from a spring scale. What would the scale  reading be if the spring scale moves up at a constant velocity of 2m/s? What about moving down at a constant velocity of 2m/s?

anonymous · Answer

The same in both cases. 

$$F = ma$$when velocity is constant, $a=0$

anonymous · Answer

so the scale would read 58.8N both times? ahh what

anonymous · Answer

Indeed. 

Let me make an analogy to driving along in a car. Imagine we had a device that measured the force between the back and your back rest. When we accelerate from a stop light, notice how this force increases as the seat back pushes against us pushing us forward. When we stop approaching a stoplight, notice how this force decreases. When we cruise at highway speeds (a constant speed that is) is this force changing?