Rolling Disk of Spruce and Steel#

A disk that will appear to roll uphill is made from spruce (\(\rho\_{\text{spruce}} = \) 429.0 \(kg/m^3\)) and steel (\(\rho\_{\text{steel}} = \) 7860.0 \(kg/m^3\)) by drilling a 3 \(cm\) diameter hole, centred 8 \(cm\) above the centre of a 30 \(cm\) diameter spruce cylinder, as shown in the figure. Into this hole is inserted a piece of steel of identical dimensions. The disk has a thickness of 23.2 \(cm\).

The figure shows a disk centred at the origin of a cartesian plane with diameter 30 cm. There is a hole of diameter 3cm centred 8 cm above the centre of the disk.

Part 1#

Calculate the mass of the spruce removed from this disk.

Answer Section#

Please enter in a numeric value in \(kg\).

Part 2#

Calculate the mass of the steel that replaces the spruce.

Answer Section#

Please enter in a numeric value in \(kg\).

Part 3#

The location of the centre of mass of the weighted disk is closest to:

Answer Section#

  • \(x\) = 1 \(cm\), \(y\) = 0 \(cm\)

  • \(x\) = 0 \(cm\), \(y\) = 1.0 \(cm\)

  • \(x\) = 0 \(cm\), \(y\) = 2.0 \(cm\)

  • \(x\) = 0 \(cm\), \(y\) = 3.0 \(cm\)

  • \(x\) = 0 \(cm\), \(y\) = 4.0 \(cm\)

  • \(x\) = 0 \(cm\), \(y\) = 0.0 \(cm\)

Attribution#

Problem is licensed under the CC-BY-NC-SA 4.0 license.
The Creative Commons 4.0 license requiring attribution-BY, non-commercial-NC, and share-alike-SA license.