Abucket of mass 2kg is whirled in a vertical circle of radius 1.20m. at the lowest point of its motion the tension in the rope supporting the bucket is 25n. find the speed of the bucket

current and voltage can both be different in different parts of a circuit so it matters where you place the ammeter and voltmete

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 =

3. dark matter

empty space could also be a simple vacuum

it is b. absorbs thermal energy