7 A car of mass 1200 kg travels along a horizontal straight road. The power provided by the car's engine is constant and equal to 20 kW . The resistance to the car's motion is constant and equal to 500 N . The car passes through the points \(A\) and \(B\) with speeds \(10 \mathrm {~m} \mathrm {~s} ^ { - 1 }\) and \(25 \mathrm {~m} \mathrm {~s} ^ { - 1 }\) respectively. The car takes 30.5 s to travel from \(A\) to \(B\).
- Find the acceleration of the car at \(A\).
- By considering work and energy, find the distance \(A B\).