You can't; you don't have enough information. The two masses need not be in any specific relation therefore you can't calculate the second mass based on the first mass. Unless you have the acceleration and the total force.
To find velocity when given mass and momentum, you can use the formula: velocity momentum / mass. Simply divide the momentum by the mass to calculate the velocity.
Multiply them: density*volume = mass
Mass = Pressure*Area
Pressure=mass/unit area
Strictly speaking if the density is given then you don't need to find it.
To find the percent by mass of a compound in a given sample, you need to divide the mass of the compound by the total mass of the sample and then multiply by 100. This will give you the percentage of the compound in the sample.
You can find the mass of an object by multiplying its volume by its density. The formula to calculate mass is: mass = volume x density. Simply plug in the given values for volume and density to calculate the mass of the object.
momentum = mass x velocity => mass = momentum / velocity
To get the potential energy when only the mass and velocity time has been given, simply multiply mass and the velocity time given.
A mass-mass problem is a kind of problem wherein a person is asked to find an answer which is also a mass. In this, a person is given mass of a compound and then asked to find the mass of another compound.
You cannot. Force = Mass*Acceleration or Mass*Rate of change of Velocity.
It's not possible.