Applications of Newton's Laws

Consequences of motion

Apparent weight and Newton's 2nd LawR = m(g + a)

Parameters

Mass60 kg
Acceleration magnitude3 m/s²

Elevator state

Results

True weight588.6 N
Apparent weight588.6 N
Difference0.0 N
Scale reads60.00 kg

Curriculum

WAECNECOIGCSESATJUPEB

šŸ“‹ Teacher notes

  • •Apparent weight = R = m(g + a). When a > 0 (accelerating up), R > mg — person feels heavier.
  • •When a < 0 (accelerating down), R < mg — person feels lighter. When a = āˆ’g (free fall), R = 0.
  • •The scale reads apparent weight, not true weight. This is what WAEC/IGCSE questions actually ask for.
  • •Common exam trap: during constant speed (a=0), the person feels exactly their true weight regardless of how fast they're going.
  • •Deceleration at the top of an upward journey = acceleration downward → lighter feeling, not heavier.

āœļø Exercises