The first law of thermodynamics describes how the heat added to a system is conserved. heat the internal energy of the system or is transformed into , or both. heat is just transformed, not created or destroyed.

The first law of thermodynamics describes how the heat added to a system is conserved.

Explanation:

According to the first law of thermodynamics:  

"Energy is not created, nor destroyed, but it is conserved."  

Therefore, this law relates the work and the transferred heat exchanged in a system through the internal energy, which is neither created nor destroyed, it is only transformed.  

In other words: The change in the internal energy of a system is equal to the net heat that is transferred to it plus the net work done on it.

convex lenses are thicker at the middle. rays of light that pass through the lens are brought closer together (they converge). a convex lens is a converging lens. when parallel rays of light pass through a convex lens the refracted rays converge at one point called the principal focus.

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