[填空题]
A 65-kg trampoline artist jumps ve 3hcf24bilcov9v (d7crtically upthe yh(z6-g-dm sp 57kward from the top of a platform with a eh gs56 y--m7dkz(h tpspeed of 5.0 m/s. ($\alpha)$ How fast is he going as he lands on the trampoline, 3.0 m below (Fig. 6-38)?$v_2$ $\approx$ m/s
(b) If the trampoline behaves like a spring with spring stiffness constant 6.2×10$^{4}$ N/m , how far does he depress it? $y_3$ = m
