A package weighing 55 N is lifted to a height of 2.0 m by pulling it up a ramp 4.4 m long. the person pulling the package exerts a force of 6.5 N. mechanical advantage of the ramp?
work input?
work output?
efficiency of machine?

pe = weightxheight = 2000x1000=2,000,000joules

when heated, the valance electrons increased their speed and transferred the heat from electron to electron.   i just took the test.

speed of light in vacuum is 300,000 km/s

speed of light in other mediums is given by the expression v = c/n, where c is the speed of light in vacuum and n is the refractive index of medium.

for the first medium v = 200,000 km/s

  so, refractive index of medium = 300000/200000 = 1.5

    1.5 refractive index is usually for glass. so first medium is glass.

for the second medium v = 250,00 km/s

so, refractive index of medium = 300000/250000 = 1.2

    1.2 refractive index is usually for water. so second medium is water.

for the third medium v = 0 km/s

so, refractive index of medium = 300000/0 = ∞

    ∞ refractive index is usually for opaque mediums. so third medium is opaque medium.