What is apparent weight? Explain the apparent weight of a person in a lift in four situations.
How to lay out the answer. Follow the frame, then write it in your own words.
1 · Define apparent weight in one line. Apparent weight is the weight a body feels: the reaction force R of the surface it stands on.
2 · Draw the lift. [Diagram: a lift with a person on a weighing machine; arrow mg down, arrow R up, arrow a for the lift's acceleration]
3 · Case 1: at rest or uniform velocity. a = 0, so R = mg: apparent weight = true weight.
4 · Case 2: moving up with acceleration a. R − mg = ma, so R = m(g + a): the person feels heavier.
5 · Case 3: moving down with acceleration a. mg − R = ma, so R = m(g − a): the person feels lighter.
6 · Case 4: free fall. a = g, so R = 0: the person is weightless, like astronauts in orbit.
7 · Real-life link. You feel heavy as a lift starts going up and light as it starts coming down.
8 · Close in one line. Apparent weight depends on the lift's acceleration, while the true weight mg stays the same.
Scoring tip: Write all four cases with the formula and the feeling (heavier, lighter, weightless). One clear lift diagram with R and mg arrows earns the drawing mark.
