Which statement about subatomic particles is not true?
a. protons and neutrons have almost the same mass.
b. protons and electrons have opposite charges.
c. unlike protons and electrons, neutrons have no charge.
d. protons and neutrons have the same charge.

What is the conversion factor between kg/m^3 and g/m^3. express your experimental values for the densities in kg/m^3.

Under the action of a constant force an object accelerates at 7.8 m/s2. what will the acceleration be if (a) the force is halved? (b) the object's mass is halved? (c) the force and the object's mass are both halved? (d) the force is halved and the object's mass is doubled?

Two point charges are separated by a certain distance. how does the strength of the electric field produced by the first charge, at the position of the second charge, change if the second charge is doubled? a. the field does not change b. the field strength decreases by half. c. the field strength doubles d. the field strength quadruples