In the lab you place a beaker that is half full of water (density pw ) on a scale. you now use a light string to suspend a piece of metal of volume v in the water. the metal is completely submerged, and none of the water spills out of the beaker.

give a symbolic expression for the change in reading of the scale. express your answer in terms of the variables pw, v, and appropriate constants. n2-n1=

N2- N1 =  V g

Explanation:

Let's use for this exercised the equilibrium relationship

        ∑ F = 0

        N -W = 0

        N = W = mg

Let's use density redefinition

       ρ = m / v

       m = ρ V

       N₁ = (ρ V) g

Repeat for when the liquid is submerged, in this case an upward thrust appears as a result of the water dispensed (rgow)

        N₂ + B - W = 0

        N₂ = W - B

        B = g

        = m / V

           =    V

        N = ρ V g -    Vg

        N2 = N1 +    V g

        N2- N1 =  V g

the minimum amperage that the current in this wire would have to have so that its weight is completely supported by the magnetic force due to earth's field, assuming that no other forces except gravity act on it

it is given that trillions of microbes make up to 1% to 3% of the body mass.

let's take average of this percentage: 2%

consider the average mass of the human body as 70 kg.

then, trillions of microbes would have mass  

therefore, 100 trillion micro-organisms would weigh:

this is an approximate value and could change depending on the mass of the human body and percentage of the microbes present in it.

average mass per microorganism =