Question

19. A wheel starting from rest is uniformly accelerated at 2 rad/s2 for 20 seconds. It is allowed to rotate uniformly
for the next 10 seconds and is finally brought to rest in next 20 seconds. The total angle rotated by the wheel
in radian) is
(2) 1200 1) 600
3) 1800 4) 300​

Answer 1

Answer:

ω = 0 + 2(20) = 40 (according to rotational equation ω = ω0 + αt)

and θ = 0 + 1/2(2)(20)2 = 400 radian

in middle uniform part angle rotated = 40*10 = 400 radian

and since acceleration in first part and retardation in last part are equal so angle rotated in last part = 400 radian

total = 1200 radian