Final answer:
The work done by an applied force of 74.5 N in pushing a crate 5.20 m horizontally is 387.40 joules (J). The work is positive because the force and displacement are in the same direction.
Step-by-step explanation:
Calculating Work Done by a Force
To calculate the work done by a force, we use the formula W = F × d × cos(θ), where W is work, F is the magnitude of the force, d is the distance over which the force is applied, and θ is the angle the force makes with the direction of motion. In this case, since the force is applied horizontally and the object moves horizontally, the angle θ is 0 degrees and the cosine of 0 degrees is 1. Therefore, the formula simplifies to W = F × d.
Using the given values, the applied force is 74.5 N and the distance is 5.20 m. Plugging these into the formula, we get:
W = 74.5 N × 5.20 m
The work done is thus:
W = 387.40 J (joules)
The positive sign indicates that the force is in the direction of the motion and therefore the work done is positive.