Please answer these two questions 1a. An optical disk drive in your computer can
ID: 1494620 • Letter: P
Question
Please answer these two questions
1a. An optical disk drive in your computer can spin a disk up to 10,000 rpm (about 1045 rad / s). If a particular disk is spun at 968.7 rad / s while it is being read, and then is allowed to come to rest over 0.435 seconds, what is the magnitude of the average angular acceleration of the disk? Answer's units are rad/s2
b. If the disk is 0.12 m in diameter, what is the magnitude of the tangential acceleration of a point 1/15 of the way out from the center of the disk? =m/s2
2. The triceps muscle in the back of the upper arm extends the forearm. This muscle in a professional boxer exerts a force of 2519 N with an effective perpendicular lever arm of 2.40 cm, producing an angular acceleration of the forearm of 125.0 rad / s2. What is the moment of inertia of the boxer's forearm?
= kg*m2
Explanation / Answer
1.)
angular-speed, w = 968.7 rad/sec,
To stop time, t = 0.435 sec,
SO,
Acceleration, a = w/t = 968.7/0.435 = 2226.89 rad/sec^2
2.)
diameter, d = 0.12 m, SO, radius, r = 012/2 = 0.06 meter,
SO,
radius of point 1/15, r1 = 0.06/15 = 0.004 meter,
THUS,
Linear-acceleration, a1 = a*r1 = 2226.89*0.004,
OR,
a1 = 8.90759 m/sec^2
3)
Torque = I*
2519 N * 0.024m = I * 125rad/s²
I = 0.484 kg·m²