PhysicsRankPREVIEWTry a problem

THE PRACTICE STUDIO

Go slowly. Ask why. Make it yours.

PRACTICE · MEMBERSIntermediate · Single correct

PRACTICE / Drag and terminal speed

Terminal balance also predicts the earlier acceleration

A falling body has mass 0.60 kg. Weight is 6.0 N and buoyancy is 1.2 N. The upward drag magnitude is bv² with b = 1.2 N·s²/m².

What is its downward acceleration when its speed is half its terminal speed?

Organize the givens & assumptions
  • m = 0.60 kg
  • Weight − buoyancy = 4.8 N
  • b = 1.2 N·s²/m²

Motion is downward in a stationary fluid; use the stated quadratic drag law, constant buoyancy and weight. The low-Reynolds Stokes law is not being assumed.

  1. A0 m/s20\ \mathrm{m/s^2}
  2. B6 m/s26\ \mathrm{m/s^2}
  3. C4 m/s24\ \mathrm{m/s^2}
  4. D8 m/s28\ \mathrm{m/s^2}

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