A wooden cube just floats inside water when a 200 gm mass is placed on it. When the mass is just removed , the cube is 2 cm above the water level. The size of the cube is ?

Asked by Paresh | 5th Dec, 2015, 07:47: PM

Expert Answer:

In initial condition:
Weight of the cube + Weight of mass placed above (200 gm) = Weight of the water displaced
Let 'l' be the side and 'd' be the density of the cube 
→l3 dg + 200 gm = l× 1 ×g
→l3 d =  l3 - 200 -------- (Equation 1)
In second case, (l - 2) part of cube remains in the water.
Thus,
ldg = l2 (l - 2)×g
Weight of the block = upthrust
From equation 1, we get
→ l- 200 = l- 2l2
or l2 = 100
or l = 10 cm

Answered by Yashvanti Jain | 6th Dec, 2015, 09:35: AM