Edexcel IAL M1 Forces and Newton's Laws Questions
Newton's three laws, resolving forces on inclines, connected particles (pulleys), friction with coefficient μ.
- M1 · Mechanics 1
- Calculator allowed
- 45 practice questions
What the questions test
The 45 M1 forces and newton's laws practice questions cover:
Worked example 1
Two particles $A$ ($4\text{ kg}$) and $B$ ($6\text{ kg}$) are connected by a light inextensible string that passes over a smooth pulley at the edge of a rough horizontal table. $A$ rests on the table (coefficient of friction $\mu = 0.2$); $B$ hangs freely. The system is released from rest. Find the acceleration and the tension in the string. Take $g = 9.8\text{ m s}^{-2}$.
Mark scheme
For $A$: $R = 4g = 39.2\text{ N}$; friction $= 0.2 \times 39.2 = 7.84\text{ N}$ M1 A1. Newton II on $A$: $T - 7.84 = 4a$ M1. Newton II on $B$: $6g - T = 6a$, i.e. $58.8 - T = 6a$ M1. Add: $58.8 - 7.84 = 10a \Rightarrow a = 5.10\text{ m s}^{-2}$ A1. Then $T = 4(5.10) + 7.84 = 28.24\text{ N}$ A1 A1.
Worked example 2
A wedge has two rough inclined faces, one at $30^{\circ}$ and the other at $45^{\circ}$ to the horizontal. A particle A of mass $2 \text{ kg}$ lies on the $30^{\circ}$ face and is connected by a light string passing over the smooth apex of the wedge to a particle B of mass $3 \text{ kg}$ on the $45^{\circ}$ face. The coefficient of friction on both faces is $0.1$. Determine the acceleration of the particles.
Mark scheme
- M1 for identifying the likely direction of motion: B ($3g \sin 45^{\circ} \approx 20.8 \text{ N}$) is heavier and on a steeper slope than A ($2g \sin 30^{\circ} = 9.8 \text{ N}$), so B will move down its plane and A up its plane.
- M1 for calculating friction on A (opposing motion, acting down): $F_A = 0.1(2g \cos 30^{\circ}) = 1.697 \text{ N}$.
- M1 for calculating friction on B (opposing motion, acting up): $F_B = 0.1(3g \cos 45^{\circ}) = 2.079 \text{ N}$.
- M1 for setting up equation of motion for A: $T - 2g \sin 30^{\circ} - F_A = 2a \implies T - 9.8 - 1.697 = 2a$.
- M1 for setting up equation of motion for B: $3g \sin 45^{\circ} - T - F_B = 3a \implies 20.789 - T - 2.079 = 3a$.
- M1 for adding equations to eliminate T: $20.789 - 2.079 - 9.8 - 1.697 = 5a \implies 7.213 = 5a$.
- A1 for finding $a = 1.44 \text{ m s}^{-2}$ (to 3 s.f.).
FAQ
What forces and newton's laws is in Edexcel IAL M1?
Newton's three laws, resolving forces on inclines, connected particles (pulleys), friction with coefficient μ.
Is M1 a calculator paper?
Yes, a calculator is allowed in M1, but method marks are only given for working you write down.
How are M1 forces and newton's laws questions marked?
With M marks for a correct method, A marks for accurate answers that depend on the M mark before them, and B marks for independent results, as in the worked examples on this page.