Physics

Problem

During a school science activity a student pulls a wooden block along a bench. a. (i) The student does

1.8\,\text{kJ}

of work while moving the block

12\,\text{m}

in the forward direction. Calculate the magnitude of the horizontal force applied on the block. b. (ii) The same work is now to be reported in

\text{N\,cm}

. Convert

1.8\,\text{kJ}

into

\text{N\,cm}

. c. (iii) If, in another trial, the student applies the same force but the block slides back

5\,\text{m}

due to a sudden jerk, determine the work done by the student in this backward motion and state its sign.