HEL A load of 400N is lifted by first class lever in which the load is situated 20m away from fulcrum and effort is situated 60m from fulcrum ,if 150N effort is applied on the lever then calculate the Mechanical Advantage and Velocity Ratio.

In a well, Water is filled up to height of 6meter, then what is the pressure exerted by liquid at the bottom of well

The Efficiency of a machine is never 100% , Why ?

Adiver named jacques observes a bubble of air rising from the bottom of a lake (where the absolute pressure is 3.50 atm) to the surface (where the pressure is 1.00 atm). the temperature at the bottom is 4.00 ∘c, and the temperature at the surface is 23.0 ∘c.what is the ratio of the volume of the bubble as it reaches the surface (vs) to its volume at the bottom (vb)? if jaques were to hold his breath the air in his lungs would be kept at a constant temperature. would it be safe for jacques to hold his breath while ascending from the bottom of the lake to the surface?