According to the law of conservation of energy, what can happen to the total energy of a system?
A. The total energy can increase if energy is transferred into the
system from surroundings.
B. The total energy can decrease when energy is lost due to energy
transformation within the system.
C. Energy must be transferred out of a system if energy is
transferred into the system so that they total energy of the system
stays the same.
D. The total energy must remain the same, but energy can change
forms and be transferred within the system.

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?