A650-kg elevator starts from rest. it moves upward for 3.00 s with constant acceleration until it reaches its cruising speed of 1.75 m/s.
(a) what is the average power of the elevator motor during this time interval?
(b) how does this power compare with the motor power when the elevator moves at its cruising speed?

(a). The average power of the elevator motor during this time interval is 5903.6 W.

(b).  The power input from motor is

Explanation:

Given that,

Mass of elevator = 650 kg

Time = 3.00 sec

Speed of the elevator = 1.75 m/s

We need to calculate the acceleration of elevator

Using formula of acceleration

(a). We need to calculate the net force on elevator is

Using formula of force

We need to calculate average velocity

Using formula of average velocity

We need to calculate the average power

Using formula of power

(b). We need to calculate the power input from motor

Using formula of power

Hence, (a). The average power of the elevator motor during this time interval is 5903.6 W.

(b).  The power input from motor is

freezing

deposition

condensation

explanation;

melting also called fusion is the process where solid becomes liquid, sublimation is the process where solid becomes gaseous without first changing to liquid, deposition involves change from gaseous to solid state, freezing involves change from liquid to solid, boiling or evaporation involves change of liquid to gaseous state, while condensation is the change from gaseous state to liquid state.

endothermic reactions involves absorption of heat from the surroundings or the environment while exothermic reactions involves loss of heat energy to the surroundings.

in this case, sublimation, evaporation and melting are endothermic reactions (gain energy from the environment) while, freezing, deposition and condensation are exothermic (loss of energy to the surroundings) reactions.