Day 133: Right Answer. Wrong Physics?
The student calculated the initial momentum of the cart no problem (0.8 kg m/s). But rather than calculate the impulse (3 N•s) and add it to the initial momentum, the student added the force multiple times — in other words, the student treated the impulse product (0.3 N)(10 s) = 3 N•s as repeated addition.
What do you think? Right or wrong?