PLEASE HELP!! A horizontal disk of mass 0.12kg and radius of 013m rotates freely

Question

PLEASE HELP!!    A horizontal disk of mass 0.12kg and radius of 013m rotates freely about a vertical axis through its center with an angular speed of 5rad/s.  A mass of 0.022kg of sticky material drops vertically onto the disk from above and sticks to the edge of the disk.  (a) What is the angular speed of the disk immediately after the material sticks to it? Right after the material sticks to the disk, the friction is added to the system and the disk slows down to a stop. (b) find the time it takes the disk to stop if the magnitude of the angular acceleration is 2rad/s^2. (c) Find the number of turns the disk completes from the time the material sticks to the time the disk stops.

Explanation / Answer

I1 (disc ) = 0.5*m*r^2 =0.5*0.12*13^2 = 10.14

I2(material) = m*r^2 = 0.022*13 ^2 = 3.718

I1*w1 = (I1+I2)*w2

10.14*5 = (10.14+3.718)*w2

w2 =3.658 rad/s

b) 3.658 = 2*t

t = 3.658/2 = 1.829 s

c) 3.658^2 = 2*2*theta

theta = 3.345 rad

1 turn = 2*pi rad

3.345 rad = 0.532 turns

Related Questions

Navigate

• Browse (All)
• Browse P
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.