Newton's third law, pulleys and connected particlesAQA A-Level Maths: Mind map

Exam questions on Newton's third law, pulleys and connected particles

1. A car of mass $1200$ kg tows a trailer of mass $400$ kg along a straight, level road, using a light horizontal tow bar. The driving force on the car is $2400$ N. Resistances to motion are negligible.
   Use Newton's third law to describe the force the trailer exerts on the tow bar.2 marks
2. Two particles $A$ and $B$, of masses $3$ kg and $5$ kg, are connected by a light inextensible string that passes over a smooth fixed pulley. The particles hang vertically with the string taut and are released from rest. Take $g=9.8$ m s⁻².
   Find the magnitude and direction of the force exerted by the string on the pulley.2 marks
3. A particle $P$ of mass $4$ kg lies on a smooth horizontal table. It is connected by a light inextensible string, passing over a smooth pulley at the edge of the table, to a particle $Q$ of mass $6$ kg that hangs freely. The string is taut and $P$ is released from rest. Take $g=9.8$ m s⁻².
   Find the acceleration of the particles.3 marks