What is considered a small velocity?

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SUMMARY

The discussion revolves around the ambiguity of defining "small velocity" in physics problems, particularly in the context of an elevator scenario where the gravitational energy is given as 2400J after 250 seconds. Participants suggest that without a specified velocity, one could assume a small value such as 0.01 m/s or half the average speed of an elevator. The conversation highlights the frustration with the need for assumptions in physics compared to more straightforward mathematical problems.

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  • Understanding of gravitational potential energy (PE = mgh)
  • Basic knowledge of kinematics and dynamics
  • Familiarity with the concept of velocity in physics
  • Ability to make assumptions based on problem context
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Homework Statement



An elevator is being pulled upwards with an small inital velocity. The elevator cable has a constant tension. After 250 seconds it stops with a gravitational energy of 2400J. Assume the acceleration due to gravity is 10. What is the mass of the elevator?

Homework Equations



PE=mgh

The Attempt at a Solution



Assume what v is then see how high it is then plug into find m.
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Anyway, when a problem says that something is traveling at a small velocity, but does not state what velocity to use, what should we take it as.

This is actually what I don't like about physics. In math if I am given an integral to solve I don't assume anything, I just do it.

I remember in thermodynamics, there was this one problem about a turbine and I tried very very hard to solve it without looking at the solutions manual. Then finally I gave up and looked at the manual and guess what. There was like 3 different assumptions you had to make an order to solve it. Thanks a lot physics.
 
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Maybe try looking up the average speed of an elevator and take half of that ... or just go with .01 m/s.
 

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