Answer:
121 Joules
6.16717 m
Explanation:
m = Mass of the rocket = 2 kg
k = Spring constant = 800 N/m
x = Compression of spring = 0.55 m
Here, the kinetic energy of the spring and rocket will balance each other

The initial velocity of the rocket is 11 m/s = u.
v = Final velocity
s = Displacement
a = Acceleration due to gravity = 9.81 m/s² = g

The maximum height of the rocket will be 6.16717 m
Potential energy is given by

The potential energy of the rocket at the maximum height will be 121 Joules
If the stereo has a dial that changes the volume of the sounds the stereo makes, the one that being done by the dial is : D. Changing the amplitude of the sound waves
Hope this helps
V = 310 m/s
f = 60 MHz = 60 × 10^6 Hz
v = xf
x = v/f
x = 310/(60 × 10^6) m
x = 5.166667 × 10^(−6) m