A block with a mass of 34.0 kg is pushed with a horizontal force of 150 N. The block moves at a constant speed across a level, rough surface a distance of 6.95 m. (a) What is the work done (in J) by the 150 N force

Complete Question

A block with a mass of 34.0 kg is pushed with a horizontal force of 150 N. The block moves at a constant speed across a level, rough surface a distance of 6.95 m.

(a) What is the work done (in J) by the 150 N force

b) find the coefficient of kinetic friction between the crate and rough surface

a

b

Explanation:

From the question we are told that

   The mass of the block is  

   The horizontal force is

   The  distance moved is

Generally the work done is mathematically represented as

=>    

=>    

Generally the net force acting on the block is  

=>   Here  

Here a is the acceleration and the value is  zero because velocity is constant

 So  

So

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.