The sketch shows a velocity-time graph for rowers in a race. Given that the race is $350 \mathrm{m}$ long and finishes at time $50 \mathrm{s},$ find the value of $v.$

A footballer kicks a ball directly towards a wall $10 \mathrm{m}$ away and walks after the ball in the same direction at a constant $2 \mathrm{m}{ \mathrm{s}}^{-1}.$ The ball starts at  $4 \mathrm{m}{ \mathrm{s}}^{-1}$ but decelerates at a constant rate of $0.5 \mathrm{m}{ \mathrm{s}}^{-2}.$ When it hits the wall it rebounds to travel away from the wall at the same speed with which it hit the wall.

What assumptions have been made in your answer?

An entrant enters a model car into a race. The car accelerates from rest at a constant rate of $2 \mathrm{m}{ \mathrm{s}}^{-2}$ down a slope. When it crosses the finishing line a firework is set off at the end of the course. The sound travels at $340 \mathrm{m}{ \mathrm{s}}^{-1}.$ The time between the entrant starting and the firework being heard at the start of the course is $12 \mathrm{s}.$

Find the actual time it took for the model car to complete the course.

A lion is watching a zebra from $35 \mathrm{m}$ behind it. Both are stationary. The lion then starts chasing by accelerating at a constant rate of $3 \mathrm{m}{ \mathrm{s}}^{-2}$ for $5 \mathrm{s}.$ Once at top speed the lion maintains that speed for $3 \mathrm{s}$ before decelerating at $0.5 \mathrm{m}{ \mathrm{s}}^{-2}.$ The zebra starts moving $1 \mathrm{s}$ after the lion started, accelerating at a constant rate of $2 \mathrm{m}{ \mathrm{s}}^{-2}$ for $7 \mathrm{s}$ before maintaining a constant speed.

Show that the lion has not caught the zebra after $8 \mathrm{s}.$

A lion is watching a zebra from $35 \mathrm{m}$ behind it. Both are stationary. The lion then starts chasing by accelerating at a constant rate of $3 \mathrm{m}{ \mathrm{s}}^{-2}$ for $5 \mathrm{s}.$ Once at top speed the lion maintains that speed for $3 \mathrm{s}$ before decelerating at $0.5 \mathrm{m}{ \mathrm{s}}^{-2}.$ The zebra starts moving $1 \mathrm{s}$ after the lion started, accelerating at a constant rate of $2 \mathrm{m}{ \mathrm{s}}^{-2}$ for $7 \mathrm{s}$ before maintaining a constant speed.

Show that the gap between them at time $t \mathrm{s},$ for $t>8,$ after the start of the lion's motion is given by $\frac{1}{4}{t}^2-5t+\frac{51}{2}$ and, hence, determine when the lion catches the zebra, or when the lion gets closest and how close it gets.

A car is behind a tractor on a single-lane straight road with one lane in each direction. Both are moving at $15 \mathrm{m}{ \mathrm{s}}^{-1}.$ The speed limit is $25 \mathrm{m}{ \mathrm{s}}^{-1},$ so the car wants to overtake. The safe distance between the car and the tractor is $20 \mathrm{m}.$

To overtake, the car goes onto the other side of the road and accelerates at a constant rate of $2 \mathrm{m}{ \mathrm{s}}^{-2}$ until reaching the speed limit, when it continues at constant speed. Show that the distance the car is ahead of the tractor at time $t s$ after it starts to accelerate is given by $t^2-20$ for $0<t⩽5,$ and deduce that the car is not a safe distance ahead of the tractor before reaching the speed limit.

A car is behind a tractor on a single-lane straight road with one lane in each direction. Both are moving at $15 \mathrm{m}{ \mathrm{s}}^{-1}.$ The speed limit is $25 \mathrm{m}{ \mathrm{s}}^{-1},$ so the car wants to overtake. The safe distance between the car and the tractor is $20 \mathrm{m}.$

The car pulls in ahead of the tractor once it is a safe distance ahead. Find the total time taken from the start of the overtaking manoeuvre until the car has safely overtaken the tractor.