A body of mass 10kg is to be raised from the bottom of the top of an inclined plane 5.0m long and 3.0m off the ground at the top. Assuming a frictionless surface, how much work must be done by a force parallel to the plane pushing the block up at a constant speed? a). 138J. b).528J c).129J d). 294J e).300J

1 a

2 b

3 b

4 d

5 d

6 d

explanation:

in physics zero. in muscle fatigue could be high

it has to be b, about 97 percent.

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.