\textbf{160-} A body slides on a smooth, inclined surface and comes down with constant velocity. Which of the following statements about this body is correct?
\textbf{A-} The work done by the normal force on the body is zero.
\textbf{B-} The mechanical energy of the body decreases.
\textbf{C-} The net force is equal to the weight.
\textbf{D-} The mechanical energy of the body remains constant.
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(1) B \hspace{1cm} (2) D \hspace{1cm} (3) A and B \hspace{1cm} (4) B and D
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