34. a steam engine operates between 300k and 600k, the maximum possible efficiency of this
engine is
a. 100%
b. 75%
c. 50%
d. 25%

c. 50%

Explanation:

The maximum efficiency of a heat engine is:

η = 1 − (Tc / Th)

where Tc is the low temperature and Th is the high temperature.

In this case, Tc = 300 K and Th = 600 K:

η = 1 − (300 / 600)

η = 0.50

The maximum possible efficiency is 50%.

568.98

explanation:

its math

the minimum constant speed at which she can catch the train is 2.7 m/s

given:

acceleration = 0.6

time = 4.5 s

to find:

velocity = ?

formula used:

from 1st kinematic equation we get,

v = u + at

u = initial speed of train = 0 m/s

v = final speed of the train

a = acceleration of the train

t = time

solution:

from 1st kinematic equation we get,

v = u + at

u = initial speed of train = 0 m/s

v = final speed of the train

a = acceleration of the train

t = time

v = 0 + (0.6 × 4.5)

v = 2.7 m/s

the minimum constant speed at which she can catch the train is 2.7 m/s