physics Q1?

Question

I have to write up a lab report after doing an experiment to determine the density of a common object (I chose a book). Now I need help finding the density. We know D=m/v and the book weighs 4 lbs. Its length is 10inches and width is 8 inches. Now using this information how would I find the mass and volume?
I also have to put the results into a chart, graph, or table but I don’t know how I would prepare that so any suggestions? Thanks.

Answer 1

First you need to use metric SI units as these are the base units in Physics.

Mass is measured in Kg and length in M.

To get the mass of the book weigh it on a set of scales.
To get its volume multiply the height of the book by its width by its depth (all measure in meters) this will give you its volume in m3.

Divide the mass in Kg by the Volumen in m3 and you have your density in Kg / m3

Now consider you want to measure the desity of something more interesting, that you can't easily dimesnion to calculate its volume.

How's about a pair of kitchen scissors.

Getting the mass is easy, we can weigh them again on scales and record the mass in Kg.

Ok, so how do we get the volume, there are a lot of geometric shapes and curves, mesuring each dimension would take ages and only give you an approximation anyway.

We are going to use Archimedes priniple to quickly determine the volume of the scissiors.

Get one bucket (that you don;t mind wrecking), draw a line inside the bucket with a permanent marker about half way up. Drill a hole in the bucket of say 1/2" diameter just above the line.

Half fill the bucket with water, so that the water level is as close to the hole as possible without water running out.

Place a measuring jug under the hole in the bucket.

Drop the scissors into the bucket, some water will come out of the hole and hopefully be caught in the measuring jug. (It is important that that all the water ends up in the jug.)

Measure the amount of water collected in the jug this is exactly the same as the volume of the scissors. As the scissors take up extra volume in the water the same amount of water is displaced as the volume the scissors are taking up.

Convert the volume of water to cubic meters, 1 litre = 0.001 m3

Divide the mass of the scissors by the volume of displaced water and you have the density of the scissors determined experimentally.

Answer 2

Density can be given in weight/volume. But here's how to convert the 4 lbs to mass which, in the English system, is slugs:

W = m*g
4 lbs = m*32 ft/s^2
m = 4 lbs / 32 (ft/s^2) = .125 slugs

But now there's a problem. volume is in units of in^3, or meter^3. You only gave length and width. What's the thickness? Multiply all 3 dimensions together and compute D = m/v.

Answer 3

i disagree with the above answer by way of fact the boat is crossing the river, no longer oppisite. different words, the boat is going perpendicular to the present of the river. a^2+b^2=c^2 20^2+6^2=c^2 c= 20.88km/hr i'm going to easily say the present is going East and the boat bypass North tan^-a million(20/6)= seventy 3.3 levels N of E. ans: 20.88km/hr at seventy 3.3 levels N of E