A5.0 kg and 7.0 kg weight are placed on opposite ends of a massless 4.0 m rod (5.0 kg on the left, 7.0 kg on the right). determine the total moment of inertia of the system and net torque if
the axis of rotation is halfway between the two masses
the axis of rotation is 0.50 m to the left of the 7.0 kg weight.
which axis of rotation produces the most torque and why?

Axis of rotation in case 2 produces the most torque than case 1

Explanation:

Moment of inertia is a quantity that determines the torque needed for a required angular acceleration about a rotational axis.

formula wise its mass multiplied by the square of distance of it from the axis of rotation.

⇒

for n number of discreet bodies,

for a rigid body,

And

      where, is torque

                    is moment of inertia and

                    is angular acceleration

Now coming to the problem,

Case 1(When the axis of rotation is halfway between the two masses):

Case 2(When the axis of rotation is 0.50 m to the left of the 7.0 kg weight):

From we know that is proportional to when angular acceleration is constant which means axis of rotation in case 2 produces the most torque than case 1 because moment of inertia in case 2 is more than that of case 1

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.