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## Homework Statement

4. Your half- finished cup of coffee has cooled down to a temperature Tc. You like your coffee to be at the perfect temperature Tp. You put your cup, containing x mL of coffee, into the microwave. Assume 1mL of coffee has a mass of 1g.

a. How much energy will it take to restore your coffee to its “perfect” temperature? Assume that coffee has the same thermal properties as water and that the cup itself gains negligible heat from the microwave.

b. The microwave delivers energy to the coffee at a rate of P watts. How much time should you set the microwave to heat your coffee to the perfect temperature?

c. If the microwave delivers 750W to the coffee, how long will it take to reheat the 140mL of the coffee from 22ºC to 83 ºC?

## Homework Equations

Q=mC(t

_{i}-t

_{f})

## The Attempt at a Solution

okay i get the first bit

Q=m.4.186.(T

_{c}-T

_{p})

in part b that gets me?

delivers energy to the coffee at a rate of P watts

how does that tell me how long it takes to heat up to

Q=m.4.186.(T

_{c}-T

_{p})

if you get what i mean