Physics question

Question

A cardboard package of mass 2.2 kg is kicked with an initial speed of 5.5 m/s. It slides along a rough horizontal surface and then stops, after travelling 4.2 m. Calculate the frictional force between the package and the surface. (answer is apparently 7.92 N)

Answer 1

First, find the acceleration. You can use the equation v_f² = v_i² + 2ax

0² = 5.5² + 2a(4.2)

a = -3.601m/s²

∑F_x = ma_x

The only force in the horizontal direction is friction, which oppose the movement of the object

F_friction = ma_x = 2.2 * -3.601 = -7.922N or 7.922N opposing the movement of the object