Man A (70kg) and Man B (90kg) are hanging motionless from a platform at rest. What is the tension TA in the top rope if the platform accelerates upward at a constant rate of 2 m/s2

The tension in the upper rope (top rope), T1 = 1,888 N

Explanation:

The Parameters that were given:

Mass A, M1 = 70kg

Mass B. M2 = 90kg

acceleration, a = 2 m/s2

Assume the rope doesn't have mass, acceleration due to gravity, g

= 9.8 m/s2

The tension, T in a platform = m (a + g)

Then the tension, T1 in the upper rope = m1 (a + g) + T2

Where T2 = Tension in the lower rope

First, we calculate T2

Since the platform accelerates upward the acceleration would be positive

T2 =  m2 (a + g)

T2 = 90kg ( 2 m/s2 + 9.8 m/s2)

T2 = 1,062N

To calculate the tension T1,

T1 = m1 (a + g) + T2

= 70kg (2 m/s2 + 9.8 m/s2) + 1062N

T1 = 1,888 N

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.