[填空题]
In a ballistic pendulum experiment, projekz2+tfii,ug8t x77oo.x g 1m yct6ceyzm eykoif5t6 bw 7/yf 33 q5l4ug(ile 1 results in a maximum height h of the pendulumy3y ewzec4 ui lf7tq/66 5gymok5b (f3 equal to 2.6 cm. A second projectile causes the the pendulum to swing twice as high, $h_2=5.2\mathrm{cm}$ The second projectile was how many times faster than the first? $v_1$ = $v_2$ ([color=rgba(0, 0, 0, 0.85)]Round to three decimal places)
