Answer
1.87 $m/s^2$
Work Step by Step
If you continue to push with the force you did in part a (84.2N), then it means you have a net force of 84.2 - 52.8 = 31.4N. Then to find the acceleration we use F = ma so we need to find the mass of the crate. If the weight is 165N and Fg = mg then that means m = 16.8kg. This means a = 31.4N / 16.8kg = 1.87 $m/s^2$