Determine the change in the internal energy of a thermodynamic system, consisting of a table and a textbook sliding

Determine the change in the internal energy of a thermodynamic system, consisting of a table and a textbook sliding over it, in the process of braking the textbook until it stops completely. The mass of the textbook is m = 300g, its initial speed is V = 2 m / s.

V0 = 2 m / s.

V = 0 m / s.

m = 300 g = 0.3 kg.

ΔU -?

According to 1 law of thermodynamics: the internal energy of the U system can be changed in two ways by performing work A or by transferring heat Q.

ΔU = A + Q.

Q = 0.

ΔU = A.

Mechanical work is equal to the change in kinetic energy: A = ΔEk.

ΔEk = m * V0 ^ 2/2.

ΔU = m * V0 ^ 2/2.

ΔU = 0.3 kg * (2 m / s) ^ 2/2 = 0.6 J.

Answer: the internal energy of the system will increase by ΔU = 0.6 J.