The right answer is B. hope this helps you :)
Answer:
The value is
or 21.45%
Explanation:
From the question we are told that
The first reservoir is at steam point
The second reservoir is at room temperature 
Generally the maximum theoretical efficiency of a Carnot engine is mathematically evaluated as

=> 
=>
Answer:
v = 79.2 m/s
Solution:
As per the question:
Mass of the object, m = 250 g = 0.250 kg
Angle, 
Coefficient of kinetic friction, 
Mass attached to the string, m = 0.200 kg
Distance, d = 30 cm = 0.03 m
Now,
The tension in the string is given by:
(1)
Also
T = m(g + a)
Thus eqn (1) can be written as:





Now, the speed is given by the third eqn of motion with initial velocity being zero:

where
u = initial velocity = 0
Thus

