1. A slope rises 15m veritcally for every 40m of its length (in horizontal direction). A car of mass 1.25t travels a distance of 150m up the slope at uniform speed. Find the work done if the frictional resistance is 40N.

2. A body of mass 0.3kg slides from rest down a plane inclined at 30 degrees to the horizontal. After sliding 30m down the plane it is found to have a speed of 10m/s. How much work has been done in overcoming friction along the plane?

3. A Swiss mountain railway car of the rack and pinion type leaves Zermatt (1608m above sea level) at 9:30am and completes the 9km journey to the Gurnergrat (3136m above sea level) at 10:15am. If the car and the passengers together have a mass of 45t, calculate the average power required by the electric motors (neglect friction).