3 A car of mass \(m \mathrm {~kg}\) is towing a trailer of mass 300 kg down a straight hill inclined at \(3 ^ { \circ }\) to the horizontal at a constant speed. There are resistance forces on the car and on the trailer, and the total work done against the resistance forces in a distance of 50 m is 40000 J . The engine of the car is doing no work and the tow-bar is light and rigid.
- Find the value of \(m\).
The resistance force on the trailer is 200 N . - Find the tension in the tow-bar between the car and the trailer.