3. A car of mass 600 kg travels along a straight horizontal road with the engine of the car working at a constant rate of \(P\) watts. The resistance to the motion of the car is modelled as a constant force of magnitude \(R\) newtons. At the instant when the speed of the car is \(15 \mathrm {~ms} ^ { - 1 }\), the magnitude of the acceleration of the car is \(0.2 \mathrm {~ms} ^ { - 2 }\). Later the same car travels up a straight road inclined at angle \(\theta\) to the horizontal, where \(\sin \theta = \frac { 1 } { 20 }\). The resistance to the motion of the car from non-gravitational forces is modelled as a constant force of magnitude \(R\) newtons. When the engine of the car is working at a constant rate of \(P\) watts, the car has a constant speed of \(10 \mathrm {~ms} ^ { - 1 }\). Find the value of \(P\).