You are standing in an elevator. The force exerted by your weight on the floor of the elevator
- AWill be zero when the lift goes up with an acceleration of 9.8 m/s²
- BWill be zero when the lift comes down with an acceleration of 9.8 m/s²
- CWill be zero when the lift moves in any direction with an acceleration of 9.8 m/s²
- DWill not be affected by the change in the rate of acceleration of the lift
Show answer and explanation
Correct answer: (b) Will be zero when the lift comes down with an acceleration of 9.8 m/s²
Explanation
The force you press on the floor (your apparent weight) in a lift is m(g − a) when the lift accelerates downwards with acceleration a.
If the lift comes down with a = g = 9.8 m/s² (as in free fall), this becomes zero: you feel weightless. Going up with acceleration, you press harder, m(g + a).