Question

An Engineering Thermodynic-Heat Transfer Quistion:

A projectile of mass 0.1 kg is moving with a velocity of 250 m/s. If the stored energy (E) in the solid is 1.5625 kJ, (a) determine the specific internal energy (u). Neglect potential energy and assume the solid to be uniform.

Answer 1

Given:

1. Mass, m=0.1kg

2. Velocity of the projectile, v=250m/s

3. Stored energy in the solid, E=1.5625kJ=1562.5J

4. Potential energy, PE is negligible

For a uniform solid,

Kinetic Energy, KE= (1/2)mv²=(1/2)*0.1*250²=3125 J

Energy, E=Kinetic Energy+Potential Energy+Internal Energy

i.e., E=KE+PE+U

Substituting the values for kinetic energy and E, we get

U=E-KE=1562.5-3125

Internal Energy, U= - 1562.5J

Specific Internal Energy, u=Internal Energy/Mass

u=-1562.5/0.1

u=-15625 J/kg

where m is the mass of the projectile

v is the velocity of the projectile

KE is the kinetic energy

PE is the potential energy

E is the stored energy

U is the internal energy and

u is the specific internal energy