## 2a.
Moments about $A: T \times 1.6\sin 70° = 6g \times 0.8\cos 30°$ | M1 A2 |
$T = 27.1$ | A1 |
(4) | |
**Given Answer** | |

## 2b.
Resolve $\leftrightarrow: F = T\cos 40$ | B1 |
Resolve $\updownarrow: R + T\cos 50 = 6g$ | M1 A1 |
Use of $F \leq \mu R$ and solve for $\mu: \mu \geq \frac{20.76}{41.38} = 0.50$ (0.502) | DM1 A1 |
(5) | |
[9] | |

**Notes for Q2:**

2(a)
- M1 for a complete method to obtain an equation in $T$ only, with usual rules (applied to all equations if more than one is used)
- N.B. Treat wrong angle(s) as A error(s)
- A2 for a correct equation (or equations) A1 A0 if one error (Allow use of $a$ and $2a$ for lengths)
- A1 for 27.1 correctly obtained (and no incorrect work seen)
- N.B. GIVEN ANSWER

Other equations:
- $\swarrow: R\cos 60 + F\cos 30 = 6g\cos 60 + T\cos 70$
- $\nwarrow: R\sin 60 + T\sin 70 = F\sin 30 + 6g\sin 60$
- $M(B): 6gl\cos 30 + F 2l\sin 30 = R 2l\cos 30$
- $M(G): Fl\sin 30 + Tl\sin 70 = Rl\cos 30$

2(b)
- B1 for $F = T\cos 40$ seen
- First M1 for a complete method, with usual rules applied to all equations used, to find $R$
- N.B. Treat wrong angle(s) as A error(s)
- First A1 for a correct equation
- Second DM1, dependent on first M1, for use of $F \leq \mu R$, and solve for $\mu$
- (Allow this M if they use $F = \mu R$ or $F < \mu R$ but final A1 not then available but M0 if they use $F \geq \mu R$ or $F > \mu R$)
- Second A1 for either $\mu \geq 0.5(0)$ or $\mu \geq 0.502$
- A0 if they also give an upper bound for $\mu$

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