Question 17
In this question you must show detailed reasoning.
A particle A A\,A of mass 4 kg lies on a horizontal surface. It is connected by a light inextensible string passing over a small smooth pulley to a hanging particle B B\,B of mass 3 kg. A constant frictional force of magnitude 5 N acts on AAA. The particles are released from rest with B B\,B at a height of 1.5 m above the floor. When B B\,B reaches the floor it stops and the string becomes slack. Use g=9.8 m s−2g=9.8\text{ m s}^{-2}g=9.8 m s−2.
a.[3]
Determine the acceleration of the particles while the string is taut.
b.[2]
Determine the tension in the string.
c.[2]
Determine the speed of A A\,A when B B\,B reaches the floor.
d.[3]
Assuming the frictional force remains 5 N, determine the total distance travelled by A A\,A before it first comes to rest.
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.