(a) How far will it move in 3.0 s, starting from rest? (Ignore friction.) M

(b) How far will it move in 3.0 s if the shopper places his 30 N child in the cart before he begins to push it? M

I figure out A but stuck on B and have no clue what to do after getting it incorrect 3 times.

for A I did F = ma a = .39 then I used V = at to get V = 1.17

then i used V^2 - V_0^2 = 2aDeltaX to get DeltaX = 1.76m

I tried using something like that for b but incorrect.

I tried finding a_x and a_y but it gave me an incorrect answer. Any pointer would be very helpful. Thanks in advance