What common household substances can turn blue litmus paper red?

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

If two students are running down the hall toward each other, trying to get to class, and they have the same mass and acceleration, what will happen when they collide? will their forces cancel out or will each one experience a reaction?

Which of the following best describes the circuit shown below?