a 20-kg box sits on a level floor. the coefficient of kinetic friction between floor and box is 0,60. how large a friction force opposes the motion of the box while moving? how much work must be done against friction to move the box 5,0 m?

To find the friction force opposing the motion of the box, we can use the equation:

Friction force (F) = coefficient of kinetic friction (μ) * Normal force (N)

The normal force is equal to the weight of the box, which is given by:

Normal force (N) = mass (m) * gravitational acceleration (g)

Given that the mass of the box (m) is 20 kg and the coefficient of kinetic friction (μ) is 0.60, the equation becomes:

F = 0.60 * (20 kg * 9.8 m/s^2)

F = 0.60 * 196 N

F = 117.6 N

Therefore, the friction force opposing the motion of the box is 117.6 N.

To calculate the work done against friction to move the box 5.0 m, we can use the equation:

Work (W) = force (F) * distance (d)

Given that the distance (d) is 5.0 m, and the friction force (F) is 117.6 N, the equation becomes:

W = 117.6 N * 5.0 m

W = 588 J

Therefore, the work done against friction to move the box 5.0 m is 588 Joules.

To determine the magnitude of the friction force that opposes the motion of the box, you need to use the formula:

Friction force = coefficient of kinetic friction × normal force

The normal force is the force exerted by the floor perpendicular to the surface of contact, which is equal to the weight of the box in this case.

1. Calculate the normal force:
The weight of the box can be found using the formula: weight = mass × acceleration due to gravity

Given that the mass of the box is 20 kg and the acceleration due to gravity is approximately 9.8 m/s²:
Weight = 20 kg × 9.8 m/s²

2. Calculate the friction force:
Friction force = 0.6 × normal force

3. Substitute the calculated normal force:
Friction force = 0.6 × (20 kg × 9.8 m/s²)

Now, let's move on to calculating the work done against friction to move the box a distance of 5.0 m.

The work done against friction is given by the formula:

Work = friction force × distance

Substitute the values:
Work = Friction force × 5.0 m

Now, use the previously calculated friction force to find the work.