The work done on an ideal gas system in an isothermal process is -400j. what is the change in internal (thermal) energy of the gas? (a) 0j (b) -400j (c) 400j (d) 200 j

The change in internal energy is zero.

(a) is correct option

Explanation:

Given that,

Work done W = -400 J

The First law of thermodynamics is law conservation of energy

Law of conservation energy is defined the total amount of energy is constant in isolated system.

The energy can not be created and destroyed but the energy can be changed from one form to other form.

The First law of thermodynamics is given by

Where,  

W = work done  by the system or on the system

= Total internal energy

Q = heat

In isothermal process, the temperature is constant

The energy can not be change and the internal energy is the function of temperature.

So, The internal energy will be zero .

Hence, The change in internal energy is zero.

temp rises, and expansion

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