Momentum And Collision

5482 Words22 Pages
CHAPTER 6 MOMENTUM AND COLLISION So far, you have learned the concept of inertia introduced and developed when we discussed Newton's lows of motion. Inertia was discussed both in terms of objects at rest and objects in motion. In this chapter we are concerned only with the concept of inertia in motion, what we call as momentum. Newton gave a more precise meaning to the idea of momentum and then went on to establish an important link between momentum and force. The work done by Newton helps to examine how the force and duration time of collision between moving objects affect their motion. 6.1 MOMENTUM AND IMPULSE LINEAR MOMENTUM We know that it's harder to stop a large truck than a small car when both are moving at the same speed. We say the truck has more momentum than the car. By momentum, we mean inertia in motion, or more precisely, the product of the mass of an object and its velocity. Momentum is represented by the symbol p. As its definition shows, momentum is a vector quantity, with its direction matching that of the velocity. Momentum has dimensions mass x length / time, and its SI units are kg. m/s. We can see from the definition that a moving object can have a large momentum if it has a large mass, a high speed, or both. A moving truck has more momentum than a car moving at the same speed because the truck has more mass. But a fast car can have more momentum than a slow moving truck. And a truck at rest has no momentum at all. On the other hand, very small objects moving with very high velocities may have a very large momentum. For example, small hailstones falling from very high clouds can have enough momentum to hurt you or cause serious damage to cars and buildings. Example 6.1 A 2250 kg pickup truck has a velocity of 25 m/s to the east. What is the momentum of the truck? Solution
Open Document