Convenience sampling can be produce biased research results. true or false?

What property is a characteristic of a substance that can be observed and does not change the identity of the substance

What is the weight of a 8-kg substance in n, kn, kg·m/s2, kgf, lbm·ft/s2, and lbf?

You throw a baseball directly upward at time =0 at an initial speed of 14.9 m/s. what is the maximum height the ball reaches above where it leaves your hand? ignore air resistance and take =9.80 m/s2.