Mass of C1 to C2 Ratio: Find the Answer

[student 1]

Homework Statement

A cylinder C1 has density D1, and C2 has density 2D1. The height of C1 is 3 times as large as height of C2, and the radius of C2 is 4 times as large as the radius of C1. Find the ratio of the mass of C1 to C2.

Homework Equations

Density=Mass/Volume
Volume of Cylinder=(pi) R^2(L)

The Attempt at a Solution

Volume of C1=(pi)R^2(3H)
Volume of C2=(pi)(4R)^2(H)

Mass of 1= D1(pi)(R)^2(3H)
Mass of 2=2D1(pi)(4R)^2(H)

SO mass of C1 to C2 would be {D1(pi)(R)^2(3H)}/{2D1(pi)(4R)^2(H)}

Answer I came up with was 3/32. Is this right?

 

[alphysicist]

Hi student_1,

Your method looks right to me. Is there something about it that doesn't seem right to you?

 

[student 1]

I got an answer totally different the first time just seeing if i was doing it right. I believe I had the wrong method at first though.

 

[physixguru]

Right.