A square is cut out of a copper sheet. Two straight scratches on the surface of the square intersect forming an angle theta. The square is heated uniformly. As a result, the angle between the scratches?a) increasesb) decreasesc) stays the samed) depends on whether theta is obtuse or acute

a) increases

Explanation:

Almost all substance or material undergoes expansion due to heating. Heat gives thermal energy to the molecules of a substance increasing their body temperature. The temperature of a substance is the measure of the average kinetic energy of the molecules of that substance. When the temperature of a substance increases, the molecules begin to agitate and try to move far from each other, leading to either a linear, area, or cubic expansion, or all three of them. Metals like copper expand very well on heating, and their expansion is relatively minute, but very observable. When the face of such a copper is scratched to give and angle, heating the copper uniformly will cause the copper to expand, leading to an increase in the angle formed.

because if the tool that you are using is not balanced it there would be false mass.