Solving Power Equation: Melting an Ice Cube

In summary, the conversation discusses the use of a power equation to determine the time it takes for an ice cube to melt in a microwave oven. The equation P = W/T is mentioned, with P representing power in watts and W representing work or energy. The question is initially misunderstood due to confusion between watts and work, but it is ultimately solved by rearranging the equation to find the time in minutes.
  • #1
dolpho
66
0
Power Equation??

Homework Statement



An ice cube is placed in a microwave oven. Suppose the oven delivers 135 W of power to the ice cube and that it takes 33200 Joules to melt it. How long does it take for the ice cube to melt?

Homework Equations



P = W / T

The Attempt at a Solution



Ok so I know the answer but this is confusing me... A unit of Power is J/second. So if we rearrange the equation and solve for T in minutes it would be.

T = W / P,

T = 135 / 33200 which doesn't give us the right equation to solve it...

Instead it would be 33200 / 135 / 60 = 4.1 minutes, But why when I rearrange the equation doesn't it make sense?
 
Last edited:
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  • #2


33200 of what units? Badly stated question. "135 of power"?

P = W/T ? What do you think P and W represent?
 
  • #3


lewando said:
33200 of what units? Badly stated question. "135 of power"?

P = W/T ? What do you think P and W represent?

Power = Watts / Time, Fixed my typo up above.

Ugh nvm I just went full retard. I read the question wrong. Ty anyway!
 
  • #4


Use power = work (or energy) / time. Power has units of Watts.
 
  • #5


lewando said:
Use power = work (or energy) / time. Power has units of Watts.

Yea that's what confused me... I mixed up watts and work. Ty!
 

Related to Solving Power Equation: Melting an Ice Cube

1. How does the power equation relate to melting an ice cube?

The power equation, P = E/t, relates to melting an ice cube because it represents the rate at which energy is transferred. In this case, the energy is being transferred as heat to the ice cube, causing it to melt.

2. What factors affect the power equation when melting an ice cube?

The factors that affect the power equation when melting an ice cube include the initial temperature of the ice cube, the amount of time it is subjected to heat, and the type of material used to transfer the heat (e.g. metal vs. plastic).

3. Can the power equation be used to determine the time it takes to melt an ice cube?

Yes, the power equation can be rearranged to solve for time, t = E/P. This means that if the amount of energy (E) and the power (P) are known, the time it takes to melt an ice cube can be calculated.

4. How does the melting point of ice affect the power equation?

The melting point of ice, 0°C or 32°F, does not directly affect the power equation. However, it is important to note that once the ice cube reaches its melting point, the heat energy being transferred will only cause the ice to melt and not increase its temperature.

5. Is the power equation the only way to melt an ice cube?

No, the power equation is just one way to understand the process of melting an ice cube. Other factors such as ambient temperature, humidity, and pressure can also affect the rate at which an ice cube melts. Additionally, other methods such as using salt or rubbing alcohol can also accelerate the melting process.

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