Q. A trolley of mass $300\, kg$ carrying a sand bag of $25\, kg$ is moving uniformly with a speed of $27\, km \,h ^{-1}$ on a frictionless track. After a while, sand starts leaking out of a hole on the trolley's floor at the rate of $0.05\, kg\, s ^{-1} .$ What is the speed of the trolley after the entire sand bag is empty?
Laws of Motion
Solution: