Physics Newtons laws of motion

Question

A 1.8 kg block is pulled across a level surface by a horizontal force of 4 N. Determine the approximate coefficient of friction between the block and the surface if the block moves at constant velocity.

Answer 1

Constant V means a = 0

So, Friction = 4N (opposite direction)

Friction = mgμ = 1.8 x 9.8 x μ = 4

Then, μ = 4 / (1.8 x 9.8 ) = 0.23