4.4 Moments Of Inertia And Rotational Motion We will now be analyzing the accele

Question

4.4 Moments Of Inertia And Rotational Motion We will now be analyzing the accelerations and motions of four equally sized discs rolling down an inclined ramp. The four discs are made of metal and plastic, and have the masses as shown above. Before we conduct any of these races" we will make predictions first. 1. If Metal Disc 1 and Metal Disc 2 were placed at the top of the incline and released simultaneously, which disc would reach the bottom first? Why? 2. If Plastic Disc 1 and Plastic Disc 2 we re placed at the top of the incline and released simultaneously, which disc would reach the bottom first? Why? 3. If Metal Disc 1 and Plastic Disc 1 were placed at the top of the incline and released simultaneously, which disc would reach the bottom first? Why? 124 128

Explanation / Answer

First we calculate moment of inertia of all
Metal disc 1 (IM1) = mr2/2 = 0.36*(2.5)2/2 = 1.125 kg-mm2
Metal disc 2 (IM2) = (1/2)m(R2 - r2) = (1/2)*(0.36)(2.52 - 1.82) = 0.5418 kg-mm2
Plastic disc 1 (IP1) = (1/2)mr2= (1/2)*(0.12)*(2.5)2 = 0.375 kg-mm2
Plastic disc 2 (IP2) = (1/2)m(R2 - r2) = (1/2)*(0.04)*(2.52 - 1.82) = 0.0602 kg -mm2
(a) Now the one with more inertia will have less acceleration so comparing two metal disc.
metal disc 1 has higher inertia therefore metal disc 2 would reach the bottom first.
(2)Compairing two plastic disc.
Plastic disc 2 would reach faster.
(3) Since metal disc 1 has higher inertia therefore plastic disc 1 will reach faster.
(4) When release all then plastic disc 2 has least inertia therefore it would reach faster.
for more options please upload it again.

Related Questions

Navigate

• Browse (All)
• Browse 4
• Subjects

---

---

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