Now let’s apply our problem-solving strategy to a system in equilibrium. To improve the acoustics in an auditorium, a sound reflector with a mass of 200 kg is suspended by a chain from the ceiling. What is its weight? What force (magnitude and direction) does the chain exert on it? What is the tension in the chain? Assume that the mass of the chain itself is negligible.

  W = 1960 N

T = 1960 N     in the upward direction

Explanation:

Let's apply Newton's second law to this exercise with acceleration equal to zero, translational equilibrium

Weight is

             W = m g

             W = 200 9.8

             W = 1960 N

In the attachment we can see a diagram

              T -W = 0

              T = W

              T = 1960 N

in the upward direction

4 photovoltaic cells are required to meet monthly energy consumption of the cabin.

Explanation:

Let suppose that PV generation system produces energy at constant energy, the number of photovoltaic system to meet energy consumption of the cabin is:

(1)

Where:

- Energy consumption of the PV system, in kilowatt-hours.

- Power generation of the PV cell, in kilowatts.

- Working times, in hours.

If we know that , and , then the number of photovoltai cells is:

4 photovoltaic cells are required to meet monthly energy consumption of the cabin.