contestada

A wooden box weighing 150 N is sliding at a constant rate over a concrete sidewalk. The force required to pull the box at a steady rate is 78 N. What is the coefficient of friction?

A. 1.9
B. 228
C. 72
D. 0.52

Respuesta :

Answer:D

Explanation:

Given

Force required to move a box at steady rate is F=78 N

Weight of Block W=150 N

If the block is moving at a steady rate then net Force acting on it is zero

Applied Force must balance the Friction force

[tex]F=f_r[/tex]

[tex]f_r=\mu N[/tex]

where N=normal Reaction

Normal reaction must be equal to weight

[tex]\mu \times 150=78[/tex]

[tex]\mu =0.52[/tex]