Force to Pascals: Solving Homework Statement

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SUMMARY

The discussion centers on calculating pressure in pascals using the formula force/area, specifically for a weight of 145 lbs (converted to 65.8 kg) and a contact area mistakenly given in cubic centimeters. The correct approach involves using the area in square meters rather than cubic centimeters. The accurate calculation yields a pressure of approximately 21.5 x 10^3 pascals, as stated in the textbook, contrasting with the incorrect calculation of 21.9 pascals. Emphasis is placed on ensuring proper unit conversion and understanding the relationship between force and area.

PREREQUISITES
  • Understanding of pressure calculation using the formula force/area
  • Knowledge of unit conversions, particularly between pounds and kilograms
  • Familiarity with metric units, specifically square meters
  • Basic principles of physics related to force and pressure
NEXT STEPS
  • Study unit conversion techniques, especially for pressure measurements
  • Learn about the relationship between force, area, and pressure in physics
  • Explore the implications of using incorrect units in calculations
  • Review examples of pressure calculations in different contexts, such as fluid mechanics
USEFUL FOR

Chemistry students, physics learners, and anyone involved in calculations related to pressure and force will benefit from this discussion.

Whalstib
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Homework Statement


In my chemistry class we have been given a formula:

force/area = Newton/m^2 = kg/ms^2 = pascal

Often I find a problem given the following info and answer:

what is the pressure exerted by someone weighing 145lbs with contact area of 300 cubic cm?

Now the formula dealing with Kg (145lbs = 65.8 kg) also has time involved with it.

How do apply this eqn. to obtain an answer in pascals?

Homework Equations



I can only apply force/area

The Attempt at a Solution



I'm making mistakes as I go...I'll get back with a closer one quickly!

Book says:
21.5 x 10^3 pa
 
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Whalstib said:

Homework Statement





In my chemistry class we have been given a formula:

force/area = Newton/m^2 = kg/ms^2 = pascal

Often I find a problem given the following info and answer:

what is the pressure exerted by someone weighing 145lbs with contact area of 300 cubic cm?

Now the formula dealing with Kg (145lbs = 65.8 kg) also has time involved with it.

How do apply this eqn. to obtain an answer in pascals?

Homework Equations



I can only apply force/area

The Attempt at a Solution



65.8/.300 = 21.9 pascals WRONG!

Book says:
21.5 x 10^3 pa

The contact area cannot be in units of cubic cm. That is a measure of volume.

Don't worry about the time units in the force equation, just stick with forces and areas to calculate pressure. Be careful with your units, and you should get the right answer.
 

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