Answer:
63.0 N
Explanation:
We need to consider the resultant of the forces acting along the surface. We have two forces:
- The component of the pull parallel to the ground, which is given by
where is the angle between the force and the ground
- The frictional force, given by
where is the coefficient of friction, m = 20 kg is the mass of the box and g=9.8 m/s^2.
The box is moving at constant velocity, this means zero acceleration, so the equation of equilibrium becomes:
From which we can find the magnitude of the pull, F: