A raft is made using a number of logs (TBD) with 25-cm diameter and 2-m-length. It is desired that a maximum 90 percent volume of each log will be submerged when carrying two boys with 400 N each. Determine the minimum number of logs that must be used. The specific gravity of the log is 0.75.
Answer:
6logs
Explanation:f
First finding the volume of the logs
V= π/4d²l
= 0.098m³
So number of logs will be
Weight of 2 boys + weight of log = buoyancy force.
So
2( 400)+ N ( Mlog x g) = density of water x volume displaced x g
2(400) = N x 0.098x 1000x 9.8 x 0.9- 0.75* 1000
N= 5.5 which is approx 6logs