- #1
tak08810
- 20
- 0
Ok this problem is really really ticking me off because it seems so damn simple.
"A rubber ball has a mass of 60.0 g and a diameter of 6.98 cm. Find the moment of inertia about its diameter. Model the ball as a thin spherical shell."
Ok so moment of interia for a sphere shaped object is 2/5Mr^2 correct? So I convert grams to kg, cm to meters, plug the numbers in (radius = 0.0349 m) and get 2.92 *10^-5 kg*m^2. But this is wrong? I don't understand what I'm doing wrong. I assume I'm looking at this problem in completely the wrong way. Here is the list of attempts I've put in:
Submission # Try Submitted Answer
1 Incorrect. (Try 1) 2.92 *10^-5 kg*m^2
2 Incorrect. (Try 2) 1.17 *10^-4 kg*m^2
3 Incorrect. (Try 3) 7.30 *10^-5 kg*m^2
4 Incorrect. (Try 4) 2.92 *10^-4 kg*m^2
5 Incorrect. (Try 5) 2.93 *10^-5 kg*m^2
6 Incorrect. (Try 6) 2.91 *10^-5 kg*m^2
7 Submission not graded. Use more digits. 2.9 *10^-5 kg*m^2
8 Submission not graded. Use fewer digits. 1.1692896 *10^-4 kg*m^2
9 Incorrect. (Try 7) 1.1692 *10^-4 kg*m^2
10 Incorrect. (Try 8) 0.000 kg*m^2
11 Incorrect. (Try 9) 0.000292 kg*m^2
12 Incorrect. (Try 10) 0.000117 kg*m^2
13 Incorrect. (Try 11) 0.0004188 kg*m^2
14 Incorrect. (Try 12) 0.004188 kg*m^2
15 Incorrect. (Try 13) 0.000251 kg*m^2
16 Incorrect. (Try 14) 0.000251 g*m^2
17 Incorrect. (Try 15) 2.92 *10^-5 kg*m^2
"A rubber ball has a mass of 60.0 g and a diameter of 6.98 cm. Find the moment of inertia about its diameter. Model the ball as a thin spherical shell."
Ok so moment of interia for a sphere shaped object is 2/5Mr^2 correct? So I convert grams to kg, cm to meters, plug the numbers in (radius = 0.0349 m) and get 2.92 *10^-5 kg*m^2. But this is wrong? I don't understand what I'm doing wrong. I assume I'm looking at this problem in completely the wrong way. Here is the list of attempts I've put in:
Submission # Try Submitted Answer
1 Incorrect. (Try 1) 2.92 *10^-5 kg*m^2
2 Incorrect. (Try 2) 1.17 *10^-4 kg*m^2
3 Incorrect. (Try 3) 7.30 *10^-5 kg*m^2
4 Incorrect. (Try 4) 2.92 *10^-4 kg*m^2
5 Incorrect. (Try 5) 2.93 *10^-5 kg*m^2
6 Incorrect. (Try 6) 2.91 *10^-5 kg*m^2
7 Submission not graded. Use more digits. 2.9 *10^-5 kg*m^2
8 Submission not graded. Use fewer digits. 1.1692896 *10^-4 kg*m^2
9 Incorrect. (Try 7) 1.1692 *10^-4 kg*m^2
10 Incorrect. (Try 8) 0.000 kg*m^2
11 Incorrect. (Try 9) 0.000292 kg*m^2
12 Incorrect. (Try 10) 0.000117 kg*m^2
13 Incorrect. (Try 11) 0.0004188 kg*m^2
14 Incorrect. (Try 12) 0.004188 kg*m^2
15 Incorrect. (Try 13) 0.000251 kg*m^2
16 Incorrect. (Try 14) 0.000251 g*m^2
17 Incorrect. (Try 15) 2.92 *10^-5 kg*m^2