Abox having a mass of 50 kg is dragged across a horizontal floor by means of a rope tied on the front of it. the coefficient of friction between the box and the floor is .3. if the angle between the rope and the floor is 30 degrees, what force must be exerted on the rope to move the box with an acceleration of 2.5 m/second squared

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?