A block of mass 20 kg is moving with velocity 10 m/s on a rough horizontal surface. Maximum amount of heat that can be generated from this block is _______.

CONCEPT:

• Energy conservation: The energy of an isolated system is conserved the energy may be transformed from one form to another form.
  • Energy can neither be created nor destroyed.
• The kinetic energy of a mass is given by

\(KE = {1 \over 2}mv^2\)

where m is the mass, v is the speed and KE is the kinetic energy.​

CALCULATION:

• Given that m = 20 kg; v = 10 m/s
• According to the law of conservation of energy, energy can neither be created nor be destroyed. It only transforms from one form to another form.
• So maximum heat will be generated when this block's whole kinetic energy is converted into heat energy. So

Maximum heat energy finally = total kinetic energy initially

Maximum heat energy finally = \( {1 \over 2}mv^2= {1 \over 2} \times 20 \times 10^2=1000 J\)

​Maximum heat generated = 1000 J = 1 kJ

• So the correct answer is option 1.