To calculate the work done by the person, we can use the formula for work:
\[ \text{Work} = \text{Force} \times \text{Distance} \times \cos(\theta) \]
Where:
- Force is the applied force (in newtons),
- Distance is the distance over which the force is applied (in meters),
- \(\theta\) is the angle between the force and the direction of motion.
In this case, since the person is pushing the box in the same direction as the force applied, \(\theta = 0\) degrees, and \(\cos(0) = 1\).
Given:
- Force = 400 N
- Distance = 4 m
Now we can calculate the work done:
\[ \text{Work} = 400 , \text{N} \times 4 , \text{m} \times \cos(0^\circ) = 400 , \text{N} \times 4 , \text{m} \times 1 = 1600 , \text{J} \]
The work done by the person in pushing the box is 1600 joules.
The additional distance the box slides after the person stops pushing (1 meter) does not count as work done by the person; it is the result of inertia. Therefore, the total work done by the person remains 1600 joules.