Answer: First, let's resolve the forces acting on the box along the horizontal axis:
T cos(30) - f = ma
where T is the tension force, f is the friction force, m is the mass of the box, and a is its acceleration.
We can also resolve the forces along the vertical axis:
T sin(30) - W = 0
where W is the weight of the box.
Solving for T and W:
T = 400 N
W = 1292 N
T sin(30) = (400 N) sin(30) = 200 N
W = 1292 N
Now we can substitute these values into the horizontal equation and solve for the acceleration:
T cos(30) - f = ma
(400 N) cos(30) - (45 N) = (m)a
(346.4 N) = (m)a
a = (346.4 N) / m
We can calculate the mass of the box using its weight:
W = mg
1292 N = m(9.81 m/s^2)
m = 131.8 kg
Now we can substitute the mass into the equation:
a = (346.4 N) / (131.8 kg)
a ≈ 2.63 m/s^2
Therefore, the correct answer is not listed. The acceleration of the box is approximately 2.63 m/s^2.
Step-by-step explanation: