The moment of inertia of the empty turntable is 1.5 kg m². With a constant torque of 2.5 N ˆ™ m, the turntable€“person system takes 3.0 s to spin from rest to an angular speed of 1.0 rad/s. What is the person€™s moment of inertia about an axis through her center of mass? Ignore friction in the turntable axle.

(a) 2.5 kg ˆ™ m²;

(b) 6.0 kg ˆ™ m²;

(c) 7.5 kg ˆ™ m²;

(d) 9.0 kg ˆ™ m²;

The moment of inertia of the human body about an axis through its center of mass is important in the application of biomechanics to sports such as diving and gymnastics. We can measure the body€™s moment of inertia in a particular position while a person remains in that position on a horizontal turntable, with the body€™s center of mass on the turntable€™s rotational axis. The turntable with the person on it is then accelerated from rest by a torque that is produced by using a rope wound around a pulley on the shaft of the turntable. From the measured tension in the rope and the angular acceleration, we can calculate the body€™s moment of inertia about an axis through its center of mass.

Transcribed Image Text:

Overhead view of a female gymnast lying in somersault position atop a turntable