Un bloque de 750 kg es empujado hacia arriba por una pista inclinada 15º respecto de la horizontal. El coeficiente de rozamiento es 0.4. Determinar la fuerza necesaria para iniciar la subida del bloque por la pista.

4776.98 N is the minimum force to start the rise.  

Explanation:

We can use the first Newton's law to find the minimum force to move the block.

So we will have:

Where:

Therefore 4776.98 N is the minimum force to move the block.

I hope it helps you!

an energy transformation flow diagram is shown

where is it ?

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.