Cue Column:

• When to use pseudo force?
• Direction?
• Is it a real force?

Notes:

A non-inertial frame is one that is accelerating. In such a frame, Newton's laws don't directly apply. We add a pseudo (fictitious) force to make them work:

F_pseudo = -m * a_frame

• m: mass of the object being analyzed
• a_frame: acceleration of the non-inertial frame
• Direction: opposite to the frame's acceleration

Example: In an elevator accelerating upward at a_0:

• Apparent weight = m(g + a_0) — feels heavier
• For downward acceleration: apparent weight = m(g - a_0) — feels lighter
• Free fall (a_0 = g): apparent weight = 0 — weightlessness

Important: Pseudo force is NOT a real force — there is no agent exerting it. It exists only in the non-inertial frame analysis. In the ground (inertial) frame, no pseudo force is needed.

Summary: Use pseudo force only when solving in a non-inertial frame. Always specify which frame you're working in.