A 15kg crate on a nearly frictionless horizontal floor is pulled to the right by a rope with a force of 50N while another worker pushes to the left with 20N. Taking the rightward direction as positive, what is the crate’s acceleration?
a) +3.3m/s2
b) +2.0m/s2
c) −2.0m/s2
d) +1.3m/s2