The radius of the wheel is 40cm and the radius of the axle is 0.1 metre in a wheel and

axle. If a load of 1200N is overcome up to 4m by applying

an effort of 400N, calculate:

i. mechanical advantage ii. velocity ratio iii. efficiency

iv. output work v. input work
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are their multiple choices ?

explanation:

fgravity=10x10=100n case 1

fgravity=30x20=600n case 2

6 times more

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.