A \(2-\mathrm{kg}\) block moving at \(4 \mathrm{~m} / \mathrm{s}\) hits a slower \(1-\mathrm{kg}\) block moving at \(2 \mathrm{~m} / \mathrm{s}\). If the \(2-\mathrm{kg}\) block continues in the same direction at \(3 \mathrm{~m} / \mathrm{s},(a)\) what is the speed of the slower block?

(b) Is the collision elastic?

(c) By what factor does the internal energy of the system change?