Although I may be wrong, A- Human activity is the answer.
Answer:
La masa de la mascota es de 11,24 kg.
Explanation:
Dado que la masa total de = 80 kg
Tenemos
Fuerza de fricción = 80 kg × 9.81 × 0.3 = 235.44 N
La mascota salta horizontalmente con una velocidad, v, de 6.0 m / s para dar un movimiento de 1 m a la caja de masa y a la persona
Trabajo realizado por el salto de la mascota = (80 - m) × 9.81 × 0.3
La energía del movimiento del perro = 1/2 × m × v² = Trabajo realizado al saltar de la mascota
1/2 × m × 6² = (80 - m) × 9.81 × 0.3
20943 · m = 235440
m = 235440/20943 = 11,24 kg
We simply use the formula,

Given, velocity = 4 m per s and distance = 120 m.
Substituting these values, we get
.
Thus, required time for the elevator in order to travel 120 m upwards is 30 s.
Answer:
Millions or hundreds of million of years
Explanation:
It takes a very long time for decaying substances to form fossil fuels. It takes around millions or hundreds of million of years for the transformation to occur. This explains why they aren’t renewable.
Decayed plant materials usually form coal while decayed animal materials form crude oil.
Chemical change is any change that results in the formation of new chemical substances. At the molecular level, chemical change involves making or breaking of bonds between atoms. These changes are chemical: iron rusting (iron oxide forms) gasoline burning (water vapor and carbon dioxide form)