# Equilibrium Question Involving boat and scale

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1. Nov 6, 2015

### Coolcatss

1. The problem statement, all variables and given/known data
A trailer carrying a boat is supported by a scale which initially reads 48 kg. The boat (and therefore its centre of gravity) is moved 0.15 m further back on the trailer. The scale now reads 37 kg. Find the mass of the boat (Ignore the 6.0 m distance because it was not given and therefore is unknown.)
http://members.shaw.ca/barry-barclay/Self-Tests/test06/q15.gif
2. Relevant equations
ΣT=0

Initial Mass= 48 kg
Final Mass= 38 kg
unknown distance of the boat= x
Center of gravity distance= 0.15 m
3. The attempt at a solution
I didn't know where to start with the x distance of the boat (used to be 6.0 m) in which, is needed to solve for the mass of boat. If someone can help put me on the right track, that would be awesome.

2. Nov 7, 2015

### haruspex

No, those are not masses. They are readings on the scale. What weights correspond to those readings?
Draw a free body diagram of the trailer. What forces act on it and where? (Put in unknowns as necessary.)
What torque balance equation looks useful?