Force & Work: Understanding the Calculus Behind it All

In summary, the conversation discusses the confusion around pounds being treated as a force instead of a mass. The explanation states that pounds are a unit of force and the slug is the unit of mass in the English system. However, the pound has been officially defined as a unit of mass and is now referred to as pound-weight to specify the gravitational force exerted by a pound.
  • #1
opticaltempest
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I am reading over an explanation of Work in my calculus textbook (Early Trancendentals 5e - Stewart). The following example has me confused. Why are pounds treated as a force and not a mass?

http://img71.imageshack.us/img71/8987/forceandwork6ok.jpg
 
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  • #2
because lbs are a unit of force. the slug is the unit of mass for the english system
 
  • #3
The pound has actually been officially defined as a unit of mass, even though I believe it was used as a unit of force a long time ago. Nowadays the term pound-weight is used to refer to the gravitational force exerted by a pound, and if you notice the main question states "20-lb weight" to specify this, even though it neglects to be so specific in the rest of the text.
 

1. What is the relationship between force and work?

The relationship between force and work can be described by the formula W = F * d, where W is work, F is force, and d is displacement. This means that work is directly proportional to the applied force and the distance over which the force is applied. In other words, the more force that is applied over a longer distance, the more work is done.

2. How is work calculated?

Work is calculated by multiplying the force applied to an object by the distance over which the force is applied. This can be expressed as W = F * d, where W is work, F is force, and d is displacement. Work is typically measured in joules (J) or newton-meters (Nm).

3. What is the difference between work and power?

Work and power are related concepts, but they are not the same thing. Work is the amount of energy transferred to an object when a force is applied and it causes the object to move. Power, on the other hand, is the rate at which work is done, or the amount of work done per unit of time. This can be expressed as P = W/t, where P is power, W is work, and t is time.

4. How is force related to acceleration?

According to Newton's Second Law of Motion, force is directly proportional to acceleration. This means that the greater the force applied to an object, the greater its acceleration will be. This can be expressed as F = ma, where F is force, m is mass, and a is acceleration. Therefore, the more force that is applied to an object, the faster it will accelerate.

5. What is the role of calculus in understanding force and work?

Calculus plays a crucial role in understanding force and work because it allows us to analyze the relationship between force, displacement, and work in a more precise and mathematical way. Calculus can be used to calculate the work done by a variable force, or to determine the force required to move an object a certain distance. It also helps us understand the concept of power, which is the rate at which work is done.

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