 #1
moenste
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Homework Statement
A bullet of mass 2.0 * 10^{3} kg is fired horizontally into a freestanding block of wood of mass 4.98 * 10^{1} kg, which it knocks forward with an initial speed of 1.2 m s^{1}.
(a) Estimate the speed of the bullet.
(b) How much kinetic energy is lost in the impact?
(c) What becomes of the lost kinetic energy?
Answers:
(a) 300 m s^{1};
(b) 89.64 J.
Homework Equations

The Attempt at a Solution
(a) 2.0 * 10^{3} kg * X m s^{1} = 4.98 * 10^{1} kg * 1.2 m s^{1}
X = 298.8 m s^{1}
(b) Kinetic energy = 1/2 * m * v^{2} = 0.5 * (2.0 * 10^{3}) * 298.8 m s^{1} = 89.28 J.
(c) Kinetic energy lost is potential energy gained.
However, as the answers don't fit the book answers 100% and I have no answer for the (c) part, I am not sure whether I am right or wrong. Any help please? Thanks in advance for any tips.