Question

A block has a mass of 7kg and on a surface with u=.7. Explain with forces, and prove mathematically, how the three situations could occur. A. The block is speeding upB. The block is slowing downC. The block is moving at a constant speed

Answer 1

A. The block has a higher force than the friction, so it continues moving and increasing the speed

$\begin{gathered} F>m\cdot g\cdot u \\ F>48.07N \end{gathered}$

B. The block has a lower force than the friction, so the acceleration is negative and the speed decrease

$\begin{gathered} FC. The block has an initial speed and the forces are the same, so the block has no acceleration, the net force is 0.[tex]\begin{gathered} F=m\cdot g\cdot u \\ F=48.07N \end{gathered}$