Physics

posted by .

Buoyancy.

A Team of 6 scouts plan to cross a lake on a raft they designed.
The dimensions of each plank is 30 cm x 30 cm x 3m.
The density of the wooden planks is of .80.
The average mass of the members is 65KG. And for their safety they want the top of the raft to be 3 cm above the surface of the water. How many wooden planks do they need to complete their project?

So far i found
V1 = .248
V = .27
P1 = .8
P = .73
using V1/V = P/P1.
Total mass of cargo ( scouts ) 6 x 65 = 390 KG. I really don't know where to go from here?!?!

  • Physics -

    Add the mass of scouts and N planks.
    That must equal the mass of displaced water.

    Plank mass (each) = 0.80*0.3*0.3*3*1000 kg/m^3
    = 216 kg

    Displaced water mass per plank:
    = 0.3*0.27*3*1000 kg/m^3
    = 243 kg

    390 + 216 N = 243 N

    N = 14.4 planks

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. science

    A team of 6 scouts plans to cross a lake on a raft they designed. The scouts have wooden beams with an average relative density of 0.80. The beams measure 30cmx30cmx3m. The average scouts' mass is about 65kg and for their safety, they …
  2. physics

    A team of 6 scouts plans to cross a lake on a raft they designed. The scouts have wooden beams with an average relative density of 0.80. The beams measure 30cmx30cmx3m. The average scouts' mass is about 65kg and for their safety, they …
  3. Physics

    A 220 kg wooden raft sits on a lake. When a 75 kg man stands on the raft, it sinks 4 cm deeper into the water. When he steps off, the raft vibrates for a while. a) What is the frequency of the raft?
  4. physics

    a raft is consttructed of wood having a density of 6000kg/m3. the surface area of the bottom of the raft is 5.7m2, and the volume of the raft is .60m3. when the raft is placed in fressh water having a density of 1000kg/m3, how deep …
  5. physics

    A raft is constructed of wood havig a density of 600kg/m^3. The surface area of the bottom of the raft is 5.7m^2 and the volume of the raft is .60m^3. When the raft is placed in fresh water having a density of 1000kg/m^3, how deep …
  6. Physical Science

    A wooden raft 3 m long x 2 m wide x 20 cm thick floats on a freshwater lake. A) Determine the buoyant force?
  7. Physical Science: PLEASE HELP!!!!!

    A wooden raft 3 m long x 2 m wide x 20 cm thick floats on a freshwater lake. A) Determine the buoyant force?
  8. physics

    A wooden raft has 85% of its volume submerged when it is floating down a river with a density of water being 9.90x10^2 kg/m^3. What is the density of the wooden raft?
  9. physics

    10 planks are required to stop the bullet in initial velocity u thickness of each planks is x and all planks are producing equal retardation find the final velocity of bullet after coming out of first plank
  10. Physics

    A raft is constructed of wood having a density of 6.00x102 kg/m3. Its surface area is 5.40 m2 and its volume is 0.45 m3. When the raft is placed in fresh water, to what depth h is the raft submerged by its weight?

More Similar Questions