Thermal energy also known as 'heat energy' is a form of kinetic energy.
A wave produced by a door bell?
There is a sound wave yes.
The Gravitationa potential energy of the mass (PEG) is given by:

where
m is the mass
g is the gravitational acceleration
h is the heigth of the mass above the reference level (the ground)
In this problem,

and

, therefore the gravitational potential energy of the mass is:
Answer:
<h2>Focal length</h2>
Explanation:
The Focal length of a lens is the distance from the center of the lens to
its principal focus.
The initial velocity of the ball is 0. Applying:
v = u + at
v = 0 + 229 x 0.08
v = 18.3 m/s
a)
Vx = Vcos(∅)
Vx = 18.3cos(52.3)
Vx = 11.2 m/s
b)
Vy = Vsin(∅)
Vy = 18.3sin(52.3)
Vy = 14.5 m/s