To find the coefficient of kinetic friction between the crate and the floor, we can use the formula for kinetic friction:
Frictional force = coefficient of kinetic friction * normal force
In this case, the normal force is equal to the weight of the crate, which is given by:
Normal force = mass * acceleration due to gravity
Normal force = 50.0 kg * 9.8 m/s^2 (acceleration due to gravity)
Normal force = 490 N
The frictional force is given by the applied force, since the crate is moving at constant velocity. So we have:
Frictional force = 70.0 N
Now we can substitute these values into the equation for kinetic friction:
70.0 N = coefficient of kinetic friction * 490 N
Solving for the coefficient of kinetic friction:
coefficient of kinetic friction = 70.0 N / 490 N
coefficient of kinetic friction ≈ 0.143
Therefore, the coefficient of kinetic friction between the crate and the floor is approximately 0.143.