6 A car of mass 900 kg is moving up a hill inclined at \(\sin ^ { - 1 } 0.12\) to the horizontal. The initial speed of the car is \(11 \mathrm {~m} \mathrm {~s} ^ { - 1 }\). After 12 s, the car has travelled 150 m up the hill and has speed \(16 \mathrm {~ms} ^ { - 1 }\). The engine of the car is working at a constant rate of 24 kW .

1. Find the work done against the resistive forces during the 12 s .
   The car then travels along a straight horizontal road. There is a resistance to the motion of the car of \(( 1520 + 4 v ) \mathrm { N }\) when the speed of the car is \(v \mathrm {~m} \mathrm {~s} ^ { - 1 }\). The car travels at a constant speed with the engine working at a constant rate of 32 kW .
2. Find this speed.