A 5kg block on a horizontal, frictionless surface is subjected to two constant forces. Force F1 has magnitude 20N and acts at 30∘ above the +x-axis. Force F2 has magnitude 15N and acts at 120∘ counter-clockwise from the +x-axis. What is the magnitude of the block’s acceleration?
a) 7m/s2
b) 6.8m/s2
c) 5m/s2
d) 5.6m/s2