How Do You Calculate Power in These Physics Problems?

In summary: Since it is being lifted at a constant speed, the only thing that is changing is the magnitude of the force. That force can be found using the equation K = (1/2) * m* V2. So, in this example, the force acting on the barbell is (1/2)*10*(3) ^2 = 30 N.For question 2, you will need to calculate the average power supplied by the firefighter. Again, since the only thing that is changing is the magnitude of the power, the power can be found using the equation P = W/T. So in this example, the average power supplied by the firefighter is (70.0)*(10.0)/(10.0*s
  • #1
SickTechz
5
0

Homework Statement


There are three problems:

1. How much power is required to lift a 10.00 kg barbell at a speed of 3.0 m/s?

2.What is the average power supplied by a 70.0 kg firefighter climbing up a ladder in 10.0 s?

3. A man pulls a wagon with a force directed 22.0˚ above the horizontal. If the horizontal component of the force on the wagon 40.5 N, what is the force exerted on the wagon?

Homework Equations



K = (1/2) * m* V2

P = W/T

The Attempt at a Solution



My physics teacher has been out and we have had a substitute that does not know physics, so I am not entirely sure how to approach these problems. In my eyes, these problems seem to be impossible to solve.[/B]
 
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  • #2
You have to provide an attempt at a solution. What have you tried?
 
  • #3
For the First problem, I would start off by plugging in 10.00 into the kinetic energy formula -> (1/2)*10*(3) ^2
then I am not sure how to find the time in order to divide them

For the second problem, I would start off by plugging in 70 for m in the kinetic energy formula. I am not sure what to do after.

For the third problem, I would plug 22 in the work formula and the force of 40.5 N -> w = (40.5)*(cos(22)) I am not sure what to do next

Like I said these problems seem to be unsolvable, but they will be on my midterm, so they must be solvable
 
  • #4
SickTechz said:
For the First problem, I would start off by plugging in 10.00 into the kinetic energy formula -> (1/2)*10*(3) ^2
then I am not sure how to find the time in order to divide them

For the first and second question...

What sort of energy is the bar bell (or fireman) gaining when it's lifted? KE? PE?
 
  • #5
SickTechz said:
For the First problem, I would start off by plugging in 10.00 into the kinetic energy formula
The question does not make it completely clear, but I would assume it means at a constant speed, i.e. don't worry about how it got to that speed - they only want the power required to keep it rising at that speed.
With that understanding, try to answer CWatter's question above.
 
  • #6
For question 1, you will need to calculate how much force is acting on the barbell.
 

FAQ: How Do You Calculate Power in These Physics Problems?

1. What is work and how is it related to energy and power?

Work is the application of a force over a distance, resulting in the transfer of energy. Energy is the ability to do work, and power is the rate at which work is done. Therefore, work, energy, and power are all interconnected and rely on each other.

2. What are the different types of energy and how are they measured?

There are several types of energy, including kinetic, potential, thermal, chemical, and electrical energy. These are measured in different units, such as joules, calories, and watts, depending on the type of energy being described.

3. What is the difference between work and power?

Work is the amount of energy transferred when a force is applied over a distance, while power is the rate at which work is done. In other words, work is a measure of how much energy is used, while power is a measure of how quickly that energy is used.

4. How is the concept of work, energy, and power applied in real-life situations?

Work, energy, and power are important concepts in physics and are used to describe and understand various natural phenomena and technological advancements. For example, work and power are used in calculating the efficiency of machines, while energy is used in the production and consumption of electricity.

5. Can energy be created or destroyed?

According to the law of conservation of energy, energy cannot be created or destroyed, it can only be transferred from one form to another. This means that the total amount of energy in a closed system remains constant, although it may change form or location.

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