Respuesta :
Answer:
Work done on the loop to stop it = 21,269.1496 J
Average power P = 924.7456 watt
Explanation:
Mass of the wheel M = 26.0 Kg
Radius r = 1.30 m
The wheel is rotating at a speed of 297 rev/min
1 minute = 60 seconds,
So,
The wheel is rotating at a speed of 297/60 rev/sec
Initial angular speed (ω₁) = 2π(297/60) = 31.1143 rad/s
Final angular speed (ω₂) = 0 rad/s
Time taken to stop , (t) = 23 s econds
Moment of inertia I of a circular hoop around its central axis = Mr²
Where m is the mass of the wheel and r is the radius of the wheel
Thus, I = 26.0×(1.30)² Kgm² = 43.94 Kgm²
(a)
Work done to stop it is the difference in the kinetic energy of the initial and the final system. So,
Work done W = (1/2)I(ω₂² - ω₁²) = 0.5*43.94(0 - (31.1143)²) = -21,269.1496 J
Thus, work done on the loop to stop it = - 21,269.1496 J
The answer has to be answered in absolute value so, Work = |-21,269.1496 J| = 21,269.1496 J
(b)
Average power P = |W|/t = 21,269.1496 J/23.0 s = 924.7456 watt
