$$W = Fd\cos\theta$$

where:

* W is the work done (in joules)

* F is the force applied (in newtons)

* d is the distance moved (in meters)

* θ is the angle between the force and the displacement (in radians)

In this case, we have a force of 2.4 N applied to a 400 g sandwich that is being pushed across a table 0.75 m wide. The coefficient of kinetic friction between the sandwich and the table is 0.1.

First, we need to calculate the force of friction acting on the sandwich:

$$F_f = \mu_k m g$$

$$F_f = (0.1)(0.4 kg)(9.8 m/s^2) = 0.392 N$$

Next, we need to calculate the angle between the force applied and the displacement:

$$\theta = \cos^{-1}\left(\frac{F_d}{F}\right)$$

$$\theta = \cos^{-1}\left(\frac{2.4 N - 0.392 N}{2.4 N}\right) = 8.5°$$

Now we can calculate the work done by the force:

$$W = Fd\cos\theta$$

$$W = (2.4 N)(0.75 m)\cos(8.5°) = 1.76 J$$

Therefore, the work done by the force in pushing the sandwich across the table is 1.76 J.