PhysicsRankPREVIEWTry a problem

THE PRACTICE STUDIO

Go slowly. Ask why. Make it yours.

PRACTICE · MEMBERSIntermediate · Single correct

PRACTICE / Newton’s law of cooling

Cooling slows near room temperature

A small body obeys Newton’s cooling law in a room at 20°C. Its cooling-rate magnitude is 6 K/min when it is at 80°C.

Find its cooling-rate magnitude when it reaches 40°C.

Organize the givens & assumptions
  • Tenv = 20°C
  • rate at 80°C = 6 K/min

Uniform body temperature; constant room temperature 20°C and constant Newton-cooling coefficient over the range.

  1. A3 K/min3\ \mathrm{K/min}
  2. B6 K/min6\ \mathrm{K/min}
  3. C18 K/min18\ \mathrm{K/min}
  4. D2 K/min2\ \mathrm{K/min}

Try it on paper first. Free sample problems in every collection include the complete reasoning: find one in this collection →