Aheat engine is 20% efficient. if it loses 800 j to the cooling system and exhaust during each cycle, the work done by the engine is:

a. 200 j
b. 1000 j
c. 800 j
d. 20 j

A. 200J

Therefore, the workdone by the heat engine is 200J

Explanation:

Given ;

The efficiency of the heat engine is E = 20% = 0.2

Heat loss L= 800J

For an heat engine the efficiency is measured by the amount of workdone by the heat engine when compared to the heat generated.

Efficiency E = workdone/heat generated × 100%

Heat generated G= workdone W + heat loss L

G = W + L

According to the question.

W = 20% of G

W = 0.2G 1

L = 80% of G

L = 0.8G

G = L/0.8 2

Substituting equation 2 to 1

W = 0.2(L/0.8)

And L = 800J

W = 0.2(800/0.8)

W = 200J

Therefore, the workdone by the heat engine is 200J

lol

explanation:

note: the given question is incomplete.

complete question is given below.

which is an example of kinetic energy?

a. the energy stored in ethanol  

b. a hockey puck sliding across the ice  

c. a compressed spring  

d. a ball sitting at the top of a ramp

solution: the kinetic energy is the energy posses by the virtue of the motion of the object.

in the given options, a, c and d are the example of potential energy because it is the energy posses by the virtue of the rest of the object. but option b has the kinetic energy as the object is in motion.

hence, a hockey puck sliding across the ice   is the apex example of kinetic energy.

so, the option (b) a hockey puck sliding across the ice   is the correct option.