5 Pressure and Density Flashcards
Define density
![](https://s3.amazonaws.com/brainscape-prod/system/cm/303/768/074/q_image_thumb.png?1527358359)
the mass per unit volume
How do you measure volume accurately when using a measuring cylinder?
Read the volume at eye level and to the bottom of the meniscus
place measuring cylinder on a level surface
![](https://s3.amazonaws.com/brainscape-prod/system/cm/303/768/075/a_image_thumb.gif?1527358034)
What is the unit for density?
g/cm3 or kg/m3
Which orientation of the block below would create in a smaller pressure on a table?
![](https://s3.amazonaws.com/brainscape-prod/system/cm/303/768/079/q_image_thumb.png?1527358565)
First orientation
P = F/A
The second block has a larger area in contact with the table, for the same force, therefore, the pressure is lower
How can the volume of an irregular object be found using a measuring cylinder?
- Half fill measuring cylinder with water and read initial volume at eye level and bottom of the meniscus
- lower object into measuring cylinder- make sure that it is fully submerged and water level has not risen above the scale
- read final volume at eye level and bottom of the meniscus
- Volume of object = final volume - initial volume
![](https://s3.amazonaws.com/brainscape-prod/system/cm/303/768/080/a_image_thumb.jpg?1527359716)
The second object has half the mass but the same volume, How does its density compare to the first object?
![](https://s3.amazonaws.com/brainscape-prod/system/cm/303/768/082/q_image_thumb.jpg?1527444294)
density = mass / volume
if mass is double for the same volume, the density doubles.
density is proportional to mass
How could you find the density of a paperclip accurately?
- measure the mass of 50 paperclips on a balance
- half fill a measuring cylinder with water and record initial volume
- carefully add 50 paperclips and record final volume.
- calculate the volume by taking the difference
- Find density = mass / volume
What is a pascal?
1 Pascal = 1 Newton per metre square
How do you find the density from a mass vs volume graph?
calculate the gradient
gradient = rise/run = mass/volume
Explain what design feature makes a knife able to cut easily.
![](https://s3.amazonaws.com/brainscape-prod/system/cm/303/768/086/q_image_thumb.jpg?1527444820)
A sharp knife with a small surface area creates a greater pressure for the same force.
pressure = force/area
The knife will cut more easily
What equation links density, mass and volume?
![](https://s3.amazonaws.com/brainscape-prod/system/cm/303/768/087/a_image_thumb.png?1527358090)
What is the unit for force?
Newton or N
Camels have adapted to walk effortlessly in the desert sand. Explain
![](https://s3.amazonaws.com/brainscape-prod/system/cm/303/768/089/q_image_thumb.jpg?1527359022)
Camels feet have a large surface area
P = F/A
A larger surface area for the same force results in lower pressure
The camel will not sink as much in the sand and can walk more easily.
How can the volume of an irregular object be measured accurately using a Eureka can?
- overfill eureka can with water and wait for water to stop dripping from the spout
- hang object from a string and slowly lower the object into the water
- make sure that the object is fully submerged
![](https://s3.amazonaws.com/brainscape-prod/system/cm/303/768/090/a_image_thumb.jpg?1527359530)
Which orientation of the block below would create a larger pressure on a table?
![](https://s3.amazonaws.com/brainscape-prod/system/cm/303/768/091/q_image_thumb.png?1527358566)
Second orientation
P = F/A
The second block has a smaller area in contact with the table for the same force, therefore, the pressure is higher