Pls

# 1

if △abc ~ △fed, which of the following statements is correct?

∠a ≅ ∠f
∠b ≅ ∠d
∠c ≅ ∠f
∠e ≅ ∠c

Amass weighing 16 pounds stretches a spring 8/3 feet. the mass is initially released from rest from a point 2 feet below the equilibrium position, and the subsequent motion takes place in a medium that offers a damping force that is numerically equal to 1/2 the instantaneous velocity. find the equation of motion if the mass is driven by an external force equal to f(t)=cos(2t).