A 6.0 kg crate is pulled across a warehouse floor by a 50 N force directed 20° below the horizontal. The coefficient of kinetic friction between the crate and the floor is 0.25. In addition, an 8 N horizontal resistive force due to air acts opposite the motion. What is the magnitude of the crate’s acceleration?
a) 5.0 m/s²
b) 3.3 m/s²
c) 4.1 m/s²
d) 2.9 m/s²