5 A train of mass 10000 kg is travelling at \(0.3 \mathrm {~m} \mathrm {~s} ^ { - 1 }\) when it collides with a buffer. The buffer brings the train to rest.
As the buffer brings the train to rest it compresses by 0.2 metres.
When the buffer is compressed by a distance of \(x\) metres it exerts a force of magnitude \(F\) newtons, where
$$F = A x + 9000 x ^ { 2 }$$
where \(A\) is a constant.
5
- Find, in terms of \(A\), the work done in compressing the buffer by 0.2 metres.
5 - Find the value of \(A\)