An open boxcar rolls at a constant speed of 6 ft/sec down a 1.5% slope. Then grain is poured in vertically downward at a rate of 500 pounds per second and at a vertical speed of 30 ft/sec when it impacts the car. Based on an analysis of the situation, will the boxcar accelerate or decelerate, and at what rate? Assume the total weight of the boxcar and its load is 5 tons.