Joe noted that the temperature in his aquarium dropped overnight. he concluded that thermal energy moved from the aquarium to the air around it. does this validate or invalidate the law of conservation of energy?

 validate                                            

Explanation:

Law of Conservation of energy

According to the law of conservation of energy, energy of a body or a system gets transferred to another system as different energy. We cannot create energy nor we can destroy energy. Energy is always transformed into other forms of energy.

In the context, Joe noticed that the aquarium's temperature dropped during the night and he concluded that according to the law of conservation of energy, the energy of the aquarium in terms of thermal energy is being transferred to the surrounding air.

This is because the aquarium is considered to be an open system where energy can come in and move out.

Hence Joe's statement is valid.

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.