Density = mass/volume or d=m/v

If less than 1kg/l, it floats. If greater than 1kg/l, it sinks. Calculate density and state if the object will sink or float.

A. Mass = 50kg. Volume = 20l
B. Mass = 4kg. Volume = 2l
C. Mass = 2.8kg. Volume = 7l

A. Density = 50kg / 20l = 2.5 kg/l

Since the density is greater than 1 kg/l, the object will sink.

B. Density = 4kg / 2l = 2 kg/l
Since the density is greater than 1 kg/l, the object will sink.

C. Density = 2.8kg / 7l = 0.4 kg/l
Since the density is less than 1 kg/l, the object will float.