A train of total mass 15000 kg travels along a straight horizontal track.
The engine provides a constant driving force of 12000 N. The total resistance to the motion of the train is constant and of magnitude 4500 N.
Find the acceleration of the train.
The driving force is now removed and a constant braking force is applied, in addition to the resistance. The train comes to rest from a speed of 20 m s−1^{-1}−1 in 25 seconds. Find the magnitude of the braking force.
139 exam-style questions on AQA A Level Maths 3.3 R: Forces and Newton's laws, covering 3.3.1 Concept of a force and Newton's first law, 3.3.2 Newton's second law, 3.3.3 Weight and motion under gravity, 3.3.4 Newton's third law and equilibrium, 3.3.5 Addition of forces and resultants (A-level only), and 3.3.6 Friction (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.