Physics help!?

Question

A block of mass 2.50 kg is pushed 2.80 m along a frictionless horizontal table by a constant 18.0 N force directed 25.0° below the horizontal.
(a) Determine the work done by the applied force.
J
(b) Determine the work done by the normal force exerted by the table.
J
(c) Determine the work done by the force of gravity.
J
(d) Determine the work done by the net force on the block.
J

Answer 1

18cos(25) = 16.31 N horizontal force.
a) W=fd so W=16.31*2.8 = 45.67 J
b) Since the table top didn't move, it did 0 work.
c) No vertical motion, no work. 0
d) 45.67 J

Doug