Question 21
In this question use g=9.8g = 9.8g=9.8 m s−2^{-2}−2.
A crate of mass 30 kg is dragged at a constant speed up a rough plane inclined at an angle of 12° 12°\,12° to the horizontal.
The crate is dragged by a rope which lies in the vertical plane containing a line of greatest slope and makes an angle of 18° 18°\,18° with the plane. The tension in the rope is T T\,T newtons.
The coefficient of friction between the crate and the plane is 0.45.
a.[6]
Find the value of TTT.
b.[2]
Explain why the tension needed would be greater if the rope were parallel to the plane.
3.3 Forces and Newton's Laws Questions
139 exam-style questions on OCR A Level Maths 3.3 Forces and Newton's Laws, covering 3.3.1 Concept and vector nature of a force, 3.3.2 Newton's first law, 3.3.3 Newton's second law in a straight line, 3.3.4 Newton's second law with vectors (A-level only), 3.3.5 Newton's second law with resolved forces (A-level only), 3.3.6 Weight, 3.3.7 Gravitational acceleration, 3.3.8 Newton's third law, 3.3.9 Normal reaction force, 3.3.10 Smooth contact model, 3.3.11 Equilibrium with connected particles and pulleys, 3.3.12 Newton's third law with resolved forces (A-level only), 3.3.13 Equilibrium by resolving (A-level only), 3.3.14 Equilibrium of forces in two dimensions using vectors (A-level only), 3.3.15 Resolving forces for advanced problems (A-level only), 3.3.16 Resultant forces and components (A-level only), 3.3.17 Dynamics of a particle in a plane (A-level only), 3.3.18 Concept of a frictional force (A-level only), 3.3.19 Contact force components (A-level only), 3.3.20 Coefficient of friction (A-level only), 3.3.21 Static and limiting equilibrium on a rough surface (A-level only), 3.3.22 Motion of a body on a rough surface (A-level only), and 3.3 Forces and Newton's Laws. Each one has a worked solution and a mark scheme showing where the marks go.