A 32-Kg Block Is Placed at the Top of a Rough

Multiple Choice

A 3.2-kg block is placed at the top of a rough incline that has a vertical height of 0.68 m and a friction coefficient of $\mu _ { k } = 0.4$ . The block is released (with a gentle push) and slides all the way down. Before it comes to rest at the bottom, the amount of thermal energy it produces is

A) 8.5 J.
B) 21 J.
C) 0 J.
D) 5.8 J.