The Halley’s Comet regularly passes by the earth on its tour around the sun (at the time of Jesus’ birth it

was something different, most probably). The semi-

major axis of the elliptical path is 17.8 AU

(astronomical unit = 150·109 m). Halley’s last visit

at our earth was in 1985. Are you going to

experience the next visit?​

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?