How much power physics question

In summary, the conversation discusses the calculation of the "real" power needed for a machine to fly based on the given amount of energy lost to air resistance. It is mentioned that the power required would be 2500 watts plus 60 watts, but the time of flight is also needed to accurately calculate the power. The conversation concludes with a suggestion to reword the question for clarity.
  • #1
tennis38
7
0
For example, if it takes 60 watts of Power for a machine to fly, yet loses (for instance) 2.5 * 10^3 Joules of its energy because of the air resistance, what's the amount of "Power" that was really given in the first place?
 
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  • #2
I'm not sure I totally understand the problem but a watt is a joule/second, so if the plane needs 60 joules per second to maintain its velocity but loses 2500 joules per second because of air resistance, then the power required would be 2500 watts + 60 watts no?
 
  • #3
Since the power is energy per second - and you have only given a total energy figure for the amount lost to air resistance, then it is not possible to calculate the "real" power without also knowing the time of flight.

But I suspect you just need to reword the question to make it clear.
 
  • #4
The time of flight is 30 minutes to reach a height of 2230 meters
 
  • #5
Simon Bridge said:
it is not possible to calculate the "real" power without also knowing the time of flight.
 
  • #6
tennis38 said:
The time of flight is 30 minutes to reach a height of 2230 meters
So if you lost 2500J in 30mins... How many J in 1sec?
 

1. How is power defined in physics?

In physics, power is defined as the rate at which work is done or energy is transferred. It is equal to the amount of work done divided by the time it takes to do the work.

2. What is the unit of measurement for power in physics?

The unit of measurement for power in physics is the watt (W). One watt is equal to one joule per second.

3. How do you calculate power?

Power can be calculated using the formula P = W/t, where P is power, W is work, and t is time.

4. What is the difference between average power and instantaneous power?

Average power is the average rate at which work is done or energy is transferred over a period of time, while instantaneous power is the power at any given moment in time.

5. How does power relate to energy?

Power is the rate at which energy is transferred or work is done. In other words, energy is equal to power multiplied by time. This means that the more power used, the faster energy is transferred or work is done.

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