পদার্থবিজ্ঞান প্রশ্ন

Along a straight horizontal road, a truck of mass 1800 kg travels. The truck's engine is working at a constant rate of 30 kW. When the truck's speed is 20 ms-1 its acceleration is 0.4 ms-2. The magnitude of the resistance to the motion of the truck is R newtons. Find the value of R.