The technology in solar panels allows us to convert the energy from the sun to energy which can be used to heat water.

electromagnetic; thermal
mechanical; electromagnetic
solar; chemical
thermal; chemica

Electromagnetic; thermal

Explanation:

The energy of the sun is transferred directly to this type of panels, to produce water heating.

This type of panels are different from the photo voltaic, which convert solar energy to electric.

see the picture for the vector

the magnitude of the vector by pythagorean theorem

r = √( (-10)^2 + (3)^2 ) = √109

magnitude = √109 units

the direction angle between vector and x-axis is

tan^(-1)(3/10) = 16.699

so the direction is approximately 16.7 degrees north of west