What is called frictional force

The density of a substance is 4.0 g/cm3. if a sample of the substance has a volume of 25 cm3 then what is the mass

Which additional product balances the reaction h2so4 + 2naoh → na2so4 + 2h2o 2oh h2o2 h3o

A200-n force is applied to the foot-operated air pump. the return spring s exerts a 2.6-n·m moment on member oba for this position. determine the corresponding compression force c in the cylinder bd. if the diameter of the piston in the cylinder is 40 mm, estimate the air pressure generated for these conditions. state any assumptions. enter a positive number for the compression force c.