Please help, I'm not sure how I keep getting this problem wrong

A contestant in a winter games event pushes a 59.0-kg rock across a frozen lake with a force of 25 N at 280 below the horizontal as shown in Figure (a) below, and it moves with an acceleration of 0.37 m/s2 to the right. (a) ( b ) (a) What is the normal force (in N) exerted by the lake surface on the rock? X Did you draw a free-body diagram and identify the forces acting on the system? Did you consider all applicable forces (or component of forces) in the vertical direction? N (b) Instead of pushing on the rock, the contestant now pulls on it with a rope over his shoulder at the same angle above the horizontal as in part (a). See Figure (b) above. Now what is the normal force (in N) exerted by the lake surface on the rock? X Consider the change in the direction of the rope in this case. N Additional Materials Reading Tutorial