A motorboat is tied to a dock with its motor running. The spinning propeller makes a surface wave that moves at a speed of 400 cm/s with a wavelength of 100 cm. What is the wave’s frequency? 4 Hz

40 Hz

0.25 Hz

25 Hz

Awater balloon launcher uses an elastic band with a spring constant of 115 n/m to use thee launcher you stretch thee band back with a balloon n it the water balloons have a mass of 1.3 kg a) if you stretch the band by 0.8 m, what elastic force will the band exert? b) with the band stretched 0.8 m, how much elastic potential energy is stored in the spring? c) if you release the band, it pushes forward. what is the kinetic energy of the balloon when it reaches the natural length of the band? d) what is the speed of the balloon when it reaches the natural length of the band?