A ball weighing 60 N is swinging like a pendulum at the end of a 6.0 m rope. As the ball swings through its lowest point, its speed is measured at 5.0 m/s. What is the
tension in the rope at this point?

Tension = 60 N

Explanation:

The ball is executing a motion like a pendulum. The lowest point of a pendulum's motion is the mean position, where its potential energy becomes zero and kinetic energy becomes maximum. At this point the rope becomes straight vertical. Hence, the tension in the rope becomes exactly equal to the weight of the object at the lowest point. Also, in this case when the ball swings through the lowest point during its motion like a pendulum, the tension in the rope will become equal to the weight of the ball.

Tension = Weight

Tension = 60 N

e

explanation:

there is no change in the electric potential energy as it is in rest on both conditions.

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.