Question

A large rotating cylinder uniformly increases in angular speed from rest to 0.220 rev/s in 31.0 s. What is its angular acceleration in radians per second per second?

(a) A large rotating cylinder uniformly increases in angular speed from rest to 0.220 rev/s in 31.0 s. What is its angular acceleration in radians per second per second? rad/s2 (b) The same cylinder again starts from rest and accelerates uniformly in the same time interval, but now the angular acceleration is double that found in part (a). What is true about the final angular speed? It is half the value given in part (a). It is the same as the value given in part (a). It is quadruple the value given in part (a). O It is double the value given in part (a).

Answer 1

Use equation of rotational kinematics after converting the angular speed from revolution per second to radian per second to find the required angular acceleration as shown below

a) a نديرا = 0, wf = 0.22 reuls 0.22X 21 radls Wi t at Wf - => 0.228 21 radls = 0 +(315) 0.0446 rad/s2 2 D wo - 'f 0+<t from above. =) Wf at So, if a wf also doubles. Hence, It is double the value given in part (a) doubles,