Problem 7-62 Energy cons. with friction - Part 3 - C
A pen of mass \(0.057 \;kg\) is sliding across a horizontal desk. In sliding \(25 \;cm\), its speed decreases to \(5.7 \;cm/s\). What was its initial speed if the force of kinetic friction exerted on the pen by the desk is \(0.15\; N\) in magnitude? Use conservation of energy.
\(E_K = (1/2)mv^2\)
The energy converted to heat is:
(A) Unknown since we are not given the coefficient of friction.
(B) Equal to the work done against the friction force.
(C) Equal to the initial kinetic energy.