[填空题]
A block of jello rests on a platfq+-loph 2 5j1vgqa- re as shj7f -pv rh9 4c*u8rkrjjj,y8xi uxf:,own in Fig. 11–58 (which also gives the dimensions of the block). You push it s,yfxxu*ju9rrj ,j8 kr8v -j:if h 4pc7ideways as shown, and then you let go. The jello springs back and begins to vibrate. In analogy to a mass vibrating on a spring, estimate the frequency of this vibration, given that the shear modulus (Section 9–5) of jello is 520 $N/m^2$ and its density is 1300 $kg/m^3$ Hz
