The spin-drier of a washing machine revolving at 900.rpm slows down uniformly to 300.rpm while making 60. revolutions. find the angular acceleration and the time required to turn through these 60. revolutions.

Acceleration is -10.57 rad/s²  

Time is 6 seconds

u=900rpm= 94.248 rad/s  

v =300rpm= 31.416 rad/s  

s=60 revolutions= 377 rad  

v²= u²+ 2as  

31.416² = 94.248²+ 2 * a * 377  

a = v²-u² / 2s

a= -10.57 rad/s²  

Using 1st equation of motion

v-u/a = t

Putting the values

t = (31.4 - 94.2)/-10.57

t = 6 seconds

i don't know that i agree with that but what's the question ?

i don't understand. explain it clearly