Recent content by C.Orio

I've found what I did wrong - I didn't put a negative sign in front of QF. Now the QTotal equals a much greater negative number, and the equations make sense. Thanks everyone for your help!

I'm not familiar with the Carnot efficiency. I'm describing efficiency as per the efficiency equation - Efficiency=EnergyOutput/EnergyInput × 100%. So if the heat that's being pumped out of the fridge is useful, then that's the 30% that is used to cool off the water... This makes sense. But now...

If the fridge was 100% efficient, then would only 1 J be needed? I'm not sure how to answer the question...

I'm not sure what you mean by "how much energy needs to be extracted from the water to cool it"... Would that be QTotal? To make the water colder, energy has to be taken from it, right? So all that thermal energy that was in the water must have been taken from the water and pumped out of the...

Homework Statement In a 30% efficient, -16°C fridge, how much electrical energy will be used up to lower the temperature of 250 mL of 75°C water? If the fridge is rated at 150 W, how long will this process take? Specific Heat Capacity of Water = 4200 J/Kg×K Specific Heat Capacity of Ice = 2000...

Thanks for the help! The only thing I'm still struggling with is why a parabola (p-t graph) has a diagonal line as a v-t graph. A parabola goes both positively and negatively (positive and negative slope from the tangent lines) but in the v-t graph all that is shown with only a diagonal line...

Hi! I'm having troubles drawing a velocity-time graph from a position-time graph. I know parabolic p-t graphs have diagonal lines for their v-t graphs, but I'm not sure why. I also know tangents are important to use, but again, I don't understand why. Any clarification as to why this happens (in...