Question

A metal piece of mass 160 g lies iln equilibrium inside a glass of water figure. The ppece touches the bottom of the glass at a small number of points. If the density of the metl is 8000 kg `m^-3`, find the normal fore exerted by the bottom of the glass on the metal piece.

A. `2N`
B. `8N`
C. `0.16N`
D. `1.4N`

Answer 1

Correct Answer - D
As the piece touches the glass at small number of points, water would be there at the bottom of the piece also and hecne buoyancy acts on it.
From equilibrium condition `mg=F_(B)+N`
`F_(B)=Vrho_("water")g=m/(rho_("metal"))xxrho_("water")xxg`
`=0.16/8xx10=0.2N`
So, `N=mg-F_(B)=160/1000xx10-0.2=1.4N`