How Is Tension Calculated for a Submerged Accelerating Object?

[smilingsteph]

Homework Statement

A lead weight with a volume of 0.69x10^-5 m^3 is lowered on a fishing line into a lake to a depth of 1.0m. What tension is required in the fishing line to give the weight an upward acceleration of 1.8m/s^2?

Homework Equations

T=F-mg F=ma D=mv D of lead= 11.34gcm^3

The Attempt at a Solution

I have tried solving it (first changing density into m, to be compatible with my volume value). Then I found the mass of the lead weight (using the given volume and measured density). But still not sure if I'm going through the proper means to arrive at the tension. Any suggestions?

 

[HallsofIvy]

Where have you used Archimedes' principal that you cite in your title? It tells you that there is an bouyancy force equal to the weight of water with the same volume as the lead weight.