Lesson: Conservation of Momentum Physics • 9th Grade
In this lesson, we will learn how to calculate the momentum changes of objects that exchange momentum with each other by applying the principle of momentum conservation.
Sample Question Videos
A firework is tied to a toy car to make a toy rocket car. The firework ejects exhaust from its base. The exhaust has a mass of 15 g and moves away from the firework at a constant speed of 55 m/s. The rocket car has a mass of 75 g. What constant speed does the rocket car move at, to the nearest integer?
A boy’s yo-yo has a mass of 20 g. The yo-yo runs down its string at a constant speed of 50 mm/s until it reaches the end of the string. When the yo-yo is at the end of the string, the boy jerks the string upward and this motion increases the upward momentum of the yo-yo by 0.0015 kg⋅m/s. At what instantaneous speed, in millimeters per second, does the yo-yo move up its string after the momentum change occurs?
A conveyer belt consists of a surface that is a sheet of material wrapped around continually turning wheels that move the surface at an average speed of 6.25 cm/s, as shown in the diagram. When a bag containing 150 g of shopping is placed on the moving surface, the surface and the shopping both have an average speed of 5 cm/s. What is the mass of the surface in grams?