When switched on, the grinding machine accelerates from rest to its operating speed of 3550 rev/min in 10 seconds. when switched off, it coasts to rest in 31 seconds. determine the number of revolutions turned during both the startup and shutdown periods. also determine the number of revolutions turned during the first half of each period. assume uniform angular acceleration in both cases.

During start total turns

After half of the time total turns

Total number of turns during it stop

After half of the time total turns

Explanation:

Initially the machine is at rest and then starts rotating with speed 3550 rev/min

now we will have

now we know that it took 10 s to reach the speed

so angular acceleration is given as

now it stops in 31 s so the angular deceleration is given as

now initially number of turn to reach the given speed

number of turns during it stop

Now during startup speed after t = 5 s is given as

now during it stop the speed after half the time is given as

now the number of turns is given as

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.