A block of mass is pulled across a horizontal table by a constant force of acting at…

PHYSICS · Multi-part · AP · Physics 1: Algebra-based · Work Energy and Power · Work Energy and Power

Problem

A block of mass

4\,\text{kg}

is pulled across a horizontal table by a constant force of

30\,\text{N}

acting at an angle of

37^{\circ}

above the horizontal. The coefficient of kinetic friction between the block and the table is

0.20

. The block moves

6\,\text{m}

along the table, starting with an initial speed of

1\,\text{m}\,\text{s}^{-1}

. Take

g = 9.8\,\text{m}\,\text{s}^{-2}

. (i) Calculate the magnitude of the kinetic friction force acting on the block. (ii) Find the work done separately by (a) the applied

30\,\text{N}

force, (b) the friction force, and (c) the weight of the block during the

6\,\text{m}

displacement. (iii) Using suitable energy considerations, determine the speed of the block after it has travelled

6\,\text{m}

. (iv) How much mechanical energy is converted into thermal energy during this motion? State your reasoning.