Physics

Problem

5\,\text{kg}

block is pulled along a straight horizontal track by a constant

60\,\text{N}

force acting in the direction of motion. During the

8\,\text{m}

displacement, a constant kinetic friction force

f

opposes the motion. The speed of the block increases from

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

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

. The magnitude of the frictional force

f

is a)

40\,\text{N}

60\,\text{N}

50\,\text{N}

45\,\text{N}