5. Now arrange for seven students to participate in five sports events, requiring that students A and B cannot participate in the same event, each event must have participants, and each person only participates in one event. Then the number of different schemes that meet the above requirements is $\qquad$
5. 15000 .

From the problem, we know there are two schemes that satisfy the conditions.
(1) One project is participated by three people, the number of schemes is $C_{7}^{3}(5!)-C_{5}^{1}(5!)=3600$;
(2) Two projects each have two people participating, the number of schemes is
$$
\frac{1}{2} \mathrm{C}_{7}^{2} \mathrm{C}_{5}^{2}(5!)-\mathrm{C}_{5}^{2}(5!)=11400 \text {. }
$$

Therefore, the number of schemes that meet the problem's requirements is
$$
3600+11400=15000 .
$$