Describe two methods a researcher can use to avoid obtaining a nonrepresentative sample

1kg of water needs to recieve 4200j of energy to go from 90 degrees to 91 degrees. what is the specific heat capacity of water? what are the units?

Which are true about beta reactions? there will be more than one answer. a. it has no change b. it doesn't change the mass of the number c. it has a mass of 0.0005 atoms d. it causes transmutation.

M1 = 2.8 kg, m2 = 6.72 kg, m3 = 11.2 kg, byas in .is ,is .toof m3 it 0.91 m. (in m/s)