Can a positive object be used to give a second object a negative charge by conduction?

What are similarities and differences between refraction, reflection, diffraction and absorption?

Need only answer if you think you know it

The experiment done in lab is repeated, using a ball that has unknown mass m. you plot your data in the form of f 2 versus m/l, with f in rev/s, m in kg, and l in m. your data falls close to a straight line that has slope 3.19 m/(kg · s2). use g = 9.80 m/s2 and calculate the mass m of the ball.