Question

The angular speed of a motor wheel is increased from 1200 rpm to 3120 rpm in 16 seconds. The angular acceleration of the motor wheel is

• A. $2 \pi \mathrm { rads } ^ { - 2 }$
• B. $4 \pi \mathrm { rads } ^ { - 2 }$
• C. $6 \pi \mathrm { rads } ^ { - 2 }$
• D. $8 \pi \mathrm { rads } ^ { - 2 }$

Answer 1

Answer: (B)

$4 \pi \mathrm { rads } ^ { - 2 }$

Answer 2

Initial angular speed,

$\omega _ { 0 } = \frac { 2 \pi \times 1200 } { 60 } \mathrm { rad } \mathrm { s } ^ { - 1 } = 40 \pi \mathrm { rad } \mathrm { s } ^ { - 1 }$

Final angular speed,

$= 104 \pi \mathrm { rad } \mathrm { s } ^ { - 1 }$

$\therefore$Angular acceleration, ,

$= 4 \pi \mathrm { rad } \mathrm { s } ^ { - 1 }$