(i) a force of 35.0 n is required to start a 6.0-kg box moving across a horizontal concrete floor, (a) what is the coefficient of static friction between the box and the floor? (b) if the 35.0-n force continues, the box accelerates at 0.60 m/s2. what is the coefficient of kinetic friction?

Respuesta :

a. The force applied would be equal to the frictional force.

F = us Fn

where, F = applied force = 35 N, us = coeff of static friction, Fn = normal force = weight

 

35 N = us * (6 kg * 9.81 m/s^2)

us = 0.595

 

b. The force applied would now be the sum of the frictional force and force due to acceleration

F = uk Fn + m a

where, uk = coeff of kinetic friction

 

35 N = uk * (6 kg * 9.81 m/s^2) + (6kg * 0.60 m/s^2)

uk = 0.533

The coefficient of static friction between the box and the floor is 0.60

The value of coefficient of kinetic friction is 0.061

Given data:

The magnitude of force to start the box is, F = 35.0 N.

The mass of box is, m = 6.0 kg.

The magnitude of acceleration is, [tex]a = 0.60 \;\rm m/s^{2}[/tex].

(a)

The force due to static friction is given as,

[tex]f = \mu mg[/tex]

Here, [tex]\mu[/tex] is the coefficient of static friction.

Solving as,

[tex]35.0= \mu \times 6 \times 9.8\\\mu \approx 0.60[/tex]

Thus, the coefficient of static friction between the box and the floor is 0.60.

(b)

If box accelerates, the frictional force comes to play to oppose the motion. Therefore,

[tex]f = F\\\mu_{k} \times m\times g = ma\\\mu_{k}\times g = a\\\mu_{k}\times 9.8 = 0.60\\\mu_{k} = 0.061[/tex]

Thus, the value of coefficient of kinetic friction is 0.061.

Learn more about the kinetic friction here:

https://brainly.com/app/ask?q=kinetic+friction