Question

A raft is made of 14 logs lashed together. Each log is 42 cm in diameter and a length of 6.4 m. 42% of the log volume is above the water when no one is on the raft. Determine the following: the specific gravity of the logs.

Answer 1

Answer:

Explanation:

Given

No of logs $n=14$

diameter of log $d=42\ cm$

Length of log $L=6.4\ m$

42 % of log volume(V) is above water when no one is on raft

so 58 % of log volume(V) is submerged in the water

Weight of 14 log

$W=14\times \rho _{log}\times V\times g$

Buoyancy force on 14 logs $F_b=14\times \rho _{water}\times 0.58V\times g$

as system is in equilibrium so

$W=F_b$  

$14\times \rho _{log}\times V\times g=14\times \rho _{water}\times 0.58V\times g$

$\rho _{log}=0.58\rho _{water}$

$\frac{\rho _{log}}{\rho _{water}}=0.58$

Specific gravity of log $=0.58$