![]() ![]() Mass and Inertia, Types of Inertia, Newton’s first law of motion.As mentioned in the previous part of this lesson, momentum is a commonly used term in sports.ICSE Worksheet for chapter-6 Newton’s Laws Of Motion class 9 Worksheet For class 9įind ICSE Worksheet for chapter-6 Newton’s Laws Of Motion class 9įor other ICSE Worksheet for class 9 Science check out main page of Physics Wallah. When a sports announcer says that a team has the momentum they mean that the team is really on the move and is going to be hard to stop. Any object with momentum is going to be hard to stop. To stop such an object, it is necessary to apply a force against its motion for a given period of time. The more momentum that an object has, the harder that it is to stop. Thus, it would require a greater amount of force or a longer amount of time or both to bring such an object to a halt. As the force acts upon the object for a given amount of time, the object's velocity is changed and hence, the object's momentum is changed. The concepts in the above paragraph should not seem like abstract information to you. You have observed this a number of times if you have watched the sport of football. In football, the defensive players apply a force for a given amount of time to stop the momentum of the offensive player who has the ball. ![]() You have also experienced this a multitude of times while driving. As you bring your car to a halt when approaching a stop sign or stoplight, the brakes serve to apply a force to the car for a given amount of time to change the car's momentum. An object with momentum can be stopped if a force is applied against it for a given amount of time. Ī force acting for a given amount of time will change an object's momentum. ![]() Put another way, an unbalanced force always accelerates an object - either speeding it up or slowing it down. If the force acts opposite the object's motion, it slows the object down. If a force acts in the same direction as the object's motion, then the force speeds the object up. Either way, a force will change the velocity of an object. And if the velocity of the object is changed, then the momentum of the object is changed. a) stated that the acceleration of an object is directly proportional to the net force acting upon the object and inversely proportional to the mass of the object.These concepts are merely an outgrowth of Newton's second law as discussed in an earlier unit. When combined with the definition of acceleration (a = change in velocity / time), the following equalities result. If both sides of the above equation are multiplied by the quantity t, a new equation results. This equation represents one of two primary principles to be used in the analysis of collisions during this unit. To truly understand the equation, it is important to understand its meaning in words. The equation really says that the Impulse = Change in momentum In words, it could be said that the force times the time equals the mass times the change in velocity. One focus of this unit is to understand the physics of collisions. The physics of collisions are governed by the laws of momentum and the first law that we discuss in this unit is expressed in the above equation. The equation is known as the impulse-momentum change equation. The law can be expressed this way: In a collision, an object experiences a force for a specific amount of time that results in a change in momentum. The result of the force acting for the given amount of time is that the object's mass either speeds up or slows down (or changes direction). The impulse experienced by the object equals the change in momentum of the object. In a collision, objects experience an impulse the impulse causes and is equal to the change in momentum. Consider a football halfback running down the football field and encountering a collision with a defensive back. The collision would change the halfback's speed and thus his momentum. If the motion was represented by a ticker tape diagram, it might appear as follows:Īt approximately the tenth dot on the diagram, the collision occurs and lasts for a certain amount of time in terms of dots, the collision lasts for a time equivalent to approximately nine dots. ![]()
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