Apiston-cylinder device contains helium gas initially at 150 kpa, 20 o c, and 0.5m 3 . the helium is now compressed in a polytropic process () to 400 kpa and 140 o c. determine the work and heat transfer done during this process.

Explanation:

Given

R for Helium

mass of gas

Similarly can be found

Work done

Since it is a polytropic Process

therefore

From Energy balance

Neglecting kinetic and Potential Energy change

Change in Internal Energy

i.e. Heat is being removed

r=rho l/a where a is the area, l is the length and rho is resistivity so the greater the area the lesser the resistance thats why the earth pin is thicker bcos current follow the shortest path, so less resistive .

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