Your heating system is 60% efficient. If it consumes 12,052 kWh of energy to heat
your house, how much useful energy(kWh) does it produce?

E = 7231.2 [kWh]

Explanation:

All systems that produce work in the mechanical form of movement or heat, they have an efficiency that depends on the construction technology, ideally in each of these equipments is that their efficiencies are as high as possible, that is, its efficiency is close to 100%. For this case we have an equipment with 60% efficiency, this heating system is characterized since of the 12,052 kWh, it uses 60% of this value only to heat the house, the rest of energy is known as lost.

E = 12,052 * (60/100)

E = 7231.2 [kWh]

This amount of energy 7231.2 [kWh] is used for heating purposes.

one person pulls 90n one way and the other has 100n pulling the other way.

so the net force = 90 - 100 = -10n,

or the ans can be 10n if the picture shows -90n and 100n instead.

this is an example of "committed" time.

committed time, as contracted time, takes need over essential and available time since it is seen as profitable work. it alludes to the time allotted to keep up a home and family. at the point when a man is commuting using committed time this individual may feel that the drive is an obligation to family, for example, strolling youngsters to class or driving a mate to work. contracted and committed time clients may feel that their commute could really compare to the commute of important or leisure time clients on the grounds that their commute is profitable work. in this manner, they might be more disposed to pick a mechanized method of movement.