To determine the work done on the box by the worker and by friction, we need to consider the work-energy principle. According to this principle, the work done on an object is equal to the change in its kinetic energy. However, since the box is moving at a constant velocity, its kinetic energy remains constant, meaning there is no change in kinetic energy. Therefore, the net work done on the box must be zero.
Now let's break down the work done by the worker and by friction:
Work done by the worker: Since the box is moving at a constant velocity, the worker's force must be equal and opposite to the force of friction. This ensures there is no net force acting on the box, resulting in zero acceleration and constant velocity. Therefore, the work done by the worker is equal in magnitude but opposite in direction to the work done by friction.
Work done by friction: Friction opposes the motion of the box, so the work done by friction is negative. The work done by friction is given by the equation W = Fd, where W is the work done, F is the force of friction, and d is the distance over which the force is applied.
Since the net work done on the box is zero, we can conclude that the magnitudes of the work done by the worker and by friction are equal. Therefore, the work done by the worker is positive and equal in magnitude to the work done by friction, but with the opposite sign.
In this case, the work done on the box by the worker is positive (+W), indicating that energy is transferred from the worker to the box. The work done on the box by friction is negative (-W), indicating that energy is transferred from the box to the frictional forces.
Hence, the magnitudes of the work done by the worker and by friction are equal, but the signs differ. The magnitude of the work done by either the worker or friction can be calculated using the equation W = Fd, where F is the force applied (either by the worker or friction) and d is the distance moved (10 m in this case). However, without information about the magnitude of the applied force or the coefficient of friction, we cannot determine the exact values of the work done by the worker or by friction.