How you work out efficiency?

What is the speed of an object at a given moment?

Which of the following is not a physical property of mattera. melting pointb.heat of combustionc. viscosityd. boiling point

Object a has a length of 3 cm, a width of 2 cm, and a height of 4 cm. object b is dropped into a graduated cylinder. it displaces 19 ml of water. the volume of object a is: a: greater than the volume of object b b: less than the volume of object b c: equal to the volume of object b