Moderate -0.8 This is a straightforward application of Newton's second law to a lift problem with given values. Students need to draw a force diagram, apply F=ma with the deceleration, and calculate R = mg - ma. It's a standard mechanics exercise requiring only direct substitution into a familiar formula, making it easier than average.
In this question use \(g = 10\) m s⁻².
A man of mass 80 kg is travelling in a lift.
The lift is rising vertically.
\includegraphics{figure_14}
The lift decelerates at a rate of 1.5 m s⁻²
Find the magnitude of the force exerted on the man by the lift.
[3 marks]
Question 14:
14 | Applies Newton’s 2nd Law to form a
3 term equation
Award mark even if signs not
correct | AO1.1a | M1 | F – 80 × 10 = –80 × 1.5
F – 800 = –120
F = 680 = 700 (N) to 1 sf
Obtains a correct 3 term equation. | AO1.1b | A1
Obtains correct reaction force.
Must be given to 1 sf
FT from incorrect 3 term equation
provided M1 mark was awarded
(condone omission of units) | AO1.1b | A1F
Total | 3
In this question use $g = 10$ m s⁻².
A man of mass 80 kg is travelling in a lift.
The lift is rising vertically.
\includegraphics{figure_14}
The lift decelerates at a rate of 1.5 m s⁻²
Find the magnitude of the force exerted on the man by the lift.
[3 marks]
\hfill \mbox{\textit{AQA AS Paper 1 Q14 [3]}}