Weighing a Salmon in an Elevator: What's the Apparent Weight?

[Snowflake9]

Homework Statement

A 5.0kg salmon is weighed by hanging it from a fish scale attached to the ceiling of an elevator. What is the apparent weight of the salmon if the elevator is (a) at rest, (b) moving upward at 2.5 m/s2, and (c) moving downward at 3.2 m/s2?

Homework Equations

Sum of F = 0
F(t) - W = 0
F(t) = W

Sum of F = Ma
F(t) - W = Ma (W=mg)

F(t)<W Sum of F = Ma
W- F(t) = Ma

The Attempt at a Solution

i have trouble thinking out of the box to get the problem started. this is my very first time ever taking physics and i have not had a math or science class in a year. can anyone help me get started?! I would appreciate any help! Thank you!

 

[kjohnson]

Part 1, you are correct. Parts 2 & 3 you have to correct formula, use F=ma. Part 2 you should get the correct answer which should be greater than the static weight. I can't tell if part 3 is a trick question since I believe that would make your "tension force" in the other direction i.e. a compression force and a rope can't carry compression...

 

[kjohnson]

brain fart..on part 3 since the acceleration is less than gravity you would still need a tension force up.

 

[Snowflake9]

thank you for the response!