![]() For simplicity, assume the meteor is traveling vertically downward prior to impact. Solutionĭefine upward to be the + y-direction. This enables us to solve for the maximum force. Next, we choose a reasonable force function for the impact event, calculate the average value of that function Figure, and set the resulting expression equal to the calculated average force. Starting off, we need to know what px is and what py is, because to find the force on the ball we can use the impulse-momentum theorem and say that Ftmv. We then use the relationship between force and impulse Figure to estimate the average force during impact. Using the given data about the meteor, and making reasonable guesses about the shape of the meteor and impact time, we first calculate the impulse using Figure. Therefore, we’ll calculate the force on the meteor and then use Newton’s third law to argue that the force from the meteor on Earth was equal in magnitude and opposite in direction. It is conceptually easier to reverse the question and calculate the force that Earth applied on the meteor in order to stop it. (credit: “Shane.torgerson”/Wikimedia Commons) Strategy The amount by which the object’s motion changes is therefore proportional to the magnitude of the force, and also to the time interval over which the force is applied.įigure 9.7 The Arizona Meteor Crater in Flagstaff, Arizona (often referred to as the Barringer Crater after the person who first suggested its origin and whose family owns the land). Alternatively, the more time you spend applying this force, again the larger the change of momentum will be, as depicted in Figure. Clearly, the larger the force, the larger the object’s change of momentum will be. Suppose you apply a force on a free object for some amount of time. The purpose of this section is to explore and describe that connection. This indicates a connection between momentum and force. An impulse applied to an object gives it momentum. If you push with 10 pounds of force for 10 seconds, or push with 100 pounds of force for 1 second, the speed it will end up moving with will be the same. Therefore, if an object’s velocity should change (due to the application of a force on the object), then necessarily, its momentum changes as well. A force applied for an amount of time is called an impulse: Imagine pushing a car in neutral. ![]() We have defined momentum to be the product of mass and velocity. Apply the impulse-momentum theorem to solve problems.By the end of this section, you will be able to:
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