Anyone that is really good at physics please message me ! ;(

An object of dimensions 50 cm x 40 cm x 0.20 cm has a mass 60g. find its density in g/cm3 and kg/ m3

Find an expression for the electric field e⃗ at the center of the semicircle. hint: a small piece of arc length δs spans a small angle δθ=δs /r, where r is the radius. express your answer in terms of the variables q, l, unit vectors i^, j^, and appropriate constants.

2) the sun is wonderful source of energy. it is renewable and natural with few dangers. solar cells rely on the sun for energy. these cells would be more practical to use if they were