The language of kinematics and motion graphsAQA A-Level Maths: Mind map

Exam questions on The language of kinematics and motion graphs

1. A runner starts at point $O$ on a straight track and runs $40$ m in the positive direction in $8$ s. She then immediately turns round and runs $15$ m back towards $O$ in $5$ s.
   Find the average speed of the runner over the whole $13$ s, and explain why it is different from the magnitude of her average velocity.2 marks
2. A train travels along a straight track. Its velocity-time graph is made of three straight-line sections: the velocity increases uniformly from $0$ to $20$ m s$^{-1}$ in $10$ s, then stays constant at $20$ m s$^{-1}$ for $30$ s, then decreases uniformly to $0$ in $20$ s.
   Find the acceleration of the train in the last $20$ s, and state what the sign of your answer tells you.2 marks
3. A cyclist travels along a straight road. Her displacement $s$ metres from a point $O$, at time $t$ seconds, has a displacement-time graph made of three straight-line sections: $s$ increases uniformly from $0$ to $100$ when $t$ goes from $0$ to $20$; $s$ stays at $100$ from $t=20$ to $t=50$; and $s$ decreases uniformly from $100$ to $40$ from $t=50$ to $t=80$.
   Find the velocity of the cyclist in each of the three stages of her journey.3 marks