You are visiting a pizza parlor and watch the chef make a pizza crust. He throws

Question

You are visiting a pizza parlor and watch the chef make a pizza crust. He throws a spinning disk of dough in the air. Its angular velocity is 15 rad/s. During the toss, its radius changes from 7.0 cm to 12.0 cm. The dough%u2019s mass is

3.25 kg, and it can be modeled as a uniform disk.

a)What is the initial angular momentum of the disk of dough?

b) What is the initial rotational KE of the disk of dough?

c)What is the final angular velocity of the disk of dough?

d) What is the final angular momentum of the dough?

e) What is the final rotational kinetic energy of the dough?

Explanation / Answer

angular momentum = I*w initial angular momentum =( M*R^2 )/ 2 a)INITIAL ANGUL MOMENTUM = mr^2/2 x w^2 = (3.25 x 0.07^2 )/ 2 x 15 = 0.1194 b)kinetic enrgy = 0.5*I*w^2 = 0.5x(3.25 x 0.07^2 )/ 2 x 15^2 =1.79*0.5 c)I1w1 = I2w2 w1/w2 = (r1/r2)^2 w2 = 44.08 rad/sec d)fInAL ANGUL MOMENTUM = mr^2/2 x w^2 = (3.25 x 0.12^2 )/ 2 x 15 = 0.35 e) final kinetic energy = 0.5*I*w^2 = 0.5x(3.25 x 0.12^2 )/ 2 x 44.08^2 =22.73

Related Questions

Navigate

• Browse (All)
• Browse Y
• Subjects

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