M1 June 2013 Q2
2. A woman travels in a lift. The mass of the woman is 50 kg and the mass of the lift is 950 kg. The lift is being raised vertically by a vertical cable which is attached to the top of the lift. The lift is moving upwards and has constant deceleration of 2 m s\(^{-2}\). By modelling the cable as being light and inextensible, find
| Scheme | Marks |
|---|---|
| For system, \((\uparrow)\), \(T - 950g - 50g = 1000 \times -2\) | M1 A1 |
| \(T = 7800\) N | A1 |
| (3) |
Notes
(In both parts, use the mass to decide which part of the system is being considered and M marks can only be scored if an equation contains only forces acting on that part of the system)
M1 is for a complete method for finding \(T\) i.e. for an equation in \(T\) only, dimensionally correct, with the correct number of terms.
First A1 for a correct equation.
Second A1 for 7800 (N).
| Scheme | Marks |
|---|---|
| For woman, \((\uparrow)\), \(R - 50g = 50 \times -2\) | M1 A1 |
| \(R = 390\) N | A1 |
| (3) | |
| (6 marks) |
Notes
M1 is for a complete method for finding \(R\) i.e. for an equation in \(R\) only, dimensionally correct, with the correct number of terms.
First A1 for a correct equation.
Second A1 for 390 (N).
N.B. Equation for lift only is: \(T - 950g - R = 950 \times (-2)\)