. You've been asked to design a heat (internal combustion) engine with an efficiency of at least 30% on a hot day, when the coolant temperature (TL) is 47°C. Assuming your engine achieves 50% of the ideal Carnot efficiency, what is the minimum temperature TH of the "hot reservoir" (combustion temperature) needed to achieve the desired actual efficiency of 30% or greater?

TH to have 30 % will be 794 degree centigrade

Step-by-step explanation:

efficiency =(TL/TH) *100% , the ideal carnot supposed to be 100 %

hence the minimum temperature of the hot reservior  Th will be half of 794 giving 159 degree centigrade

2 & 7

step-by-step explanation:

he climbs 300 ft/hr at a constant rate. the peak is at 1,500 ft.

when going up, he reaches 600 ft in 2 hours. remember, that he is going in a constant rate. divide 600 with 300:

600/300 = 2

assuming that he takes the same route back (meaning that it's a 1500 ft route back, you can solve.

note also that you are solving when he gets back to 600 ft after he reaches the peak.

first, find the amount of hours it takes to get up the peak. divide the total amount (1500), with the ft/her (300) to get the amount of hours (x):

1500/300 = x

x = 5

it takes jamie 5 hours to get up. now, he is returning down, and reaches 600 (his current destination). remember that he climbs at a constant 300 ft/hr. divide 600 with 300:

600/300 = x

x = 2

now add the two numbers together.

x = 5 + 2 = 7

jamie takes 7 hours to go up the mountain and reach his current position when descending.

(total amount/constant rate) = (time).

remember that it is a constant rate, so in total, when he gets back down the mountain, it will take the same amount of time as when he goes up. the total amount for the round trip is: 5 + 5 = 10.

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answer: options

step-by-step explanation: