Ahelicopter carrying supplies is traveling eastward, 80.0 m off the ground, at a speed of 40.0 m/s. the supplies are to be dropped from the helicopter to land in the back of a parked pickup truck on a flat road. when the helicopter and the truck are 300 m apart,
(a) how many seconds later should the helicopter crew drop the supplies?
(b) if the pickup truck was traveling westward at 25.0 mi/h from the beginning, then at what time should the helicopter crew drop the supplies?

a) Helicopter need to drop the supply after 3.46 seconds.

b) Helicopter need to drop the supply after 1.83 seconds.

Explanation:

a) Let us find time of flight of supplies that is vertical motion of supplies,

We have equation of motion s = ut + 0.5at²

          Initial velocity, u = 0 m/s

         Acceleration, a = 9.81 m/s²

         Displacement, s = 80 m

    Substituting,

                  s = ut + 0.5 at²

                 80 = 0 x t + 0.5 x 9.81 x t²

                    t = 4.04 s

  Distance traveled by helicopter in 4.04 seconds at 40 m/s = 4.04 x 40 = 161.54 m

  Distance helicopter can fly without dropping supply = 300 - 161.54 = 138.46 m

 Time taken for this

   So helicopter need to drop the supply after 3.46 seconds.

b) Speed of truck = 25 mi/h = 11.11 m/s westward

   Speed of helicopter = 40 m/s eastward

   Relative velocity, = 40 + 11.11 = 51.11 m/s

  We have equation of motion s = ut + 0.5at²

          Initial velocity, u = 0 m/s

         Acceleration, a = 9.81 m/s²

         Displacement, s = 80 m

    Substituting,

                  s = ut + 0.5 at²

                 80 = 0 x t + 0.5 x 9.81 x t²

                    t = 4.04 s

  Distance traveled by relative bodies  in 4.04 seconds at 51.11 m/s = 4.04 x 51.11 = 206.48 m

  Distance helicopter can fly without dropping supply = 300 - 206.48 = 93.52 m

 Time taken for this

   So helicopter need to drop the supply after 1.83 seconds.  

answer: the correct answer is   air pressure at the top of mount everest is higher than at the bottom of the grand canyon.

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explanation:

bacteria that live on the ocean floor are sustained by phytoplankton. phytoplankton, microscopic marine photosynthetic organisms, have a vastly significant role to play not only in the marine food web of which they’re part of, but also on a more global scale. despite their infinitely small size in comparison to other marine organisms, these tiny creatures occupy an immensely important ecological niche: they are the foundation of the marine food web, and as primary producers, play key roles in supporting all other organisms in the marine environment, as well as in the regulation of the earth’s climate through the sequestration of carbon, oxygen production, and other related processes. phytoplankton account for roughly half of all global primary productivity; therefore, their significance extends far beyond the marine environment alone. there is an intriguing sense of irony in the realization that these tiny living beings that often live out their existence unnoticed and undetected by the rest of the world, have such a far-reaching impact on the lives of virtually all other living organisms on the planet, particularly on those in the marine environment. the world that we have become accustomed to has been and is continuously shaped by the workings of these miniscule yet vital “plants of the sea”.

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