1. Given a rectangular prism of metal with a length of 4.6 cm,a width of 3.5 cm,a height of 2.0 cm,and a mass of 171g:


a. What is the block's volume?


b. What is the block's density?


2. Supposed you are determining the volume of an object  by fluid displacement and trapped some air in the cylinder as you dropped your object in.


a. Would your measured volume be higher or lower than the actual density of the object?


b. Would your calculated density be higher or lower than the actual density of the object?

If you could help,thank you.

I want to really understand how it works so I have an easier time doing this and so I can be able to do this by myself.

Guest Sep 7, 2017

1+0 Answers





volume of rectangular prism  =  ( length )(   width  )( height )

                                               =  ( 4.6 cm )( 3.5 cm )( 2.0 cm )

                                               =  32.2 cm3



By definition....   density  =  mass / volume

                                        = 171 g / 32.2 cm3

                                        ≈  5.3  g / cm3         [ grams per cubic cm ]





I imagined dropping an upside down metal cup in the cylinder. There's air trapped in the cup.....and if the air is taking up that space, then the water can't . So....when you measure the volume, you will be measuring the volume of the metal cup and the volume of the air. So....the measured volume will be higher than the actual volume of the cup.



The higher the volume with a given mass, the less dense the object is. So, your calculated density would be lower than the actual density.

hectictar  Sep 8, 2017

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